diff --git a/api4/apitestlib.go b/api4/apitestlib.go
index 39abf6b7fe..cc457dd231 100644
--- a/api4/apitestlib.go
+++ b/api4/apitestlib.go
@@ -380,14 +380,14 @@ func (th *TestHelper) InitBasic() *TestHelper {
 	th.BasicPost = th.CreatePost()
 	th.LinkUserToTeam(th.BasicUser, th.BasicTeam)
 	th.LinkUserToTeam(th.BasicUser2, th.BasicTeam)
-	th.App.AddUserToChannel(th.BasicUser, th.BasicChannel)
-	th.App.AddUserToChannel(th.BasicUser2, th.BasicChannel)
-	th.App.AddUserToChannel(th.BasicUser, th.BasicChannel2)
-	th.App.AddUserToChannel(th.BasicUser2, th.BasicChannel2)
-	th.App.AddUserToChannel(th.BasicUser, th.BasicPrivateChannel)
-	th.App.AddUserToChannel(th.BasicUser2, th.BasicPrivateChannel)
-	th.App.AddUserToChannel(th.BasicUser, th.BasicDeletedChannel)
-	th.App.AddUserToChannel(th.BasicUser2, th.BasicDeletedChannel)
+	th.App.AddUserToChannel(th.BasicUser, th.BasicChannel, false)
+	th.App.AddUserToChannel(th.BasicUser2, th.BasicChannel, false)
+	th.App.AddUserToChannel(th.BasicUser, th.BasicChannel2, false)
+	th.App.AddUserToChannel(th.BasicUser2, th.BasicChannel2, false)
+	th.App.AddUserToChannel(th.BasicUser, th.BasicPrivateChannel, false)
+	th.App.AddUserToChannel(th.BasicUser2, th.BasicPrivateChannel, false)
+	th.App.AddUserToChannel(th.BasicUser, th.BasicDeletedChannel, false)
+	th.App.AddUserToChannel(th.BasicUser2, th.BasicDeletedChannel, false)
 	th.App.UpdateUserRoles(th.BasicUser.Id, model.SYSTEM_USER_ROLE_ID, false)
 	th.Client.DeleteChannel(th.BasicDeletedChannel.Id)
 	th.LoginBasic()
@@ -792,7 +792,7 @@ func (th *TestHelper) LinkUserToTeam(user *model.User, team *model.Team) {
 func (th *TestHelper) AddUserToChannel(user *model.User, channel *model.Channel) *model.ChannelMember {
 	utils.DisableDebugLogForTest()
 
-	member, err := th.App.AddUserToChannel(user, channel)
+	member, err := th.App.AddUserToChannel(user, channel, false)
 	if err != nil {
 		panic(err)
 	}
diff --git a/api4/channel.go b/api4/channel.go
index 8e29c71880..aadc01c216 100644
--- a/api4/channel.go
+++ b/api4/channel.go
@@ -1540,7 +1540,10 @@ func addChannelMember(c *Context, w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	cm, err := c.App.AddChannelMember(member.UserId, channel, c.App.Session().UserId, postRootId)
+	cm, err := c.App.AddChannelMember(member.UserId, channel, app.ChannelMemberOpts{
+		UserRequestorID: c.App.Session().UserId,
+		PostRootID:      postRootId,
+	})
 	if err != nil {
 		c.Err = err
 		return
diff --git a/api4/channel_local.go b/api4/channel_local.go
index f0c3c54f18..6648d324f9 100644
--- a/api4/channel_local.go
+++ b/api4/channel_local.go
@@ -107,7 +107,7 @@ func localAddChannelMember(c *Context, w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	cm, err := c.App.AddUserToChannel(user, channel)
+	cm, err := c.App.AddUserToChannel(user, channel, false)
 	if err != nil {
 		c.Err = err
 		return
diff --git a/api4/channel_test.go b/api4/channel_test.go
index 224907d8c1..2eea5419df 100644
--- a/api4/channel_test.go
+++ b/api4/channel_test.go
@@ -16,6 +16,7 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
+	"github.com/mattermost/mattermost-server/v5/app"
 	"github.com/mattermost/mattermost-server/v5/model"
 	"github.com/mattermost/mattermost-server/v5/plugin/plugintest/mock"
 	"github.com/mattermost/mattermost-server/v5/store/storetest/mocks"
@@ -1497,8 +1498,8 @@ func TestDeleteChannel(t *testing.T) {
 
 		// successful delete of channel with multiple members
 		publicChannel3 := th.CreatePublicChannel()
-		th.App.AddUserToChannel(user, publicChannel3)
-		th.App.AddUserToChannel(user2, publicChannel3)
+		th.App.AddUserToChannel(user, publicChannel3, false)
+		th.App.AddUserToChannel(user2, publicChannel3, false)
 		_, resp = client.DeleteChannel(publicChannel3.Id)
 		CheckNoError(t, resp)
 
@@ -1574,9 +1575,9 @@ func TestDeleteChannel2(t *testing.T) {
 	// channels created by SystemAdmin
 	publicChannel6 := th.CreateChannelWithClient(th.SystemAdminClient, model.CHANNEL_OPEN)
 	privateChannel7 := th.CreateChannelWithClient(th.SystemAdminClient, model.CHANNEL_PRIVATE)
-	th.App.AddUserToChannel(user, publicChannel6)
-	th.App.AddUserToChannel(user, privateChannel7)
-	th.App.AddUserToChannel(user, privateChannel7)
+	th.App.AddUserToChannel(user, publicChannel6, false)
+	th.App.AddUserToChannel(user, privateChannel7, false)
+	th.App.AddUserToChannel(user, privateChannel7, false)
 
 	// successful delete by user
 	_, resp := Client.DeleteChannel(publicChannel6.Id)
@@ -1594,9 +1595,9 @@ func TestDeleteChannel2(t *testing.T) {
 	// channels created by SystemAdmin
 	publicChannel6 = th.CreateChannelWithClient(th.SystemAdminClient, model.CHANNEL_OPEN)
 	privateChannel7 = th.CreateChannelWithClient(th.SystemAdminClient, model.CHANNEL_PRIVATE)
-	th.App.AddUserToChannel(user, publicChannel6)
-	th.App.AddUserToChannel(user, privateChannel7)
-	th.App.AddUserToChannel(user, privateChannel7)
+	th.App.AddUserToChannel(user, publicChannel6, false)
+	th.App.AddUserToChannel(user, privateChannel7, false)
+	th.App.AddUserToChannel(user, privateChannel7, false)
 
 	// cannot delete by user
 	_, resp = Client.DeleteChannel(publicChannel6.Id)
@@ -2295,7 +2296,7 @@ func TestUpdateChannelRoles(t *testing.T) {
 	channel := th.CreatePublicChannel()
 
 	// Adds User 2 to the channel, making them a channel member by default.
-	th.App.AddUserToChannel(th.BasicUser2, channel)
+	th.App.AddUserToChannel(th.BasicUser2, channel, false)
 
 	// User 1 promotes User 2
 	pass, resp := Client.UpdateChannelRoles(channel.Id, th.BasicUser2.Id, ChannelAdmin)
@@ -2803,9 +2804,9 @@ func TestRemoveChannelMember(t *testing.T) {
 	t.Run("success", func(t *testing.T) {
 		// Setup the system administrator to listen for websocket events from the channels.
 		th.LinkUserToTeam(th.SystemAdminUser, th.BasicTeam)
-		_, err := th.App.AddUserToChannel(th.SystemAdminUser, th.BasicChannel)
+		_, err := th.App.AddUserToChannel(th.SystemAdminUser, th.BasicChannel, false)
 		require.Nil(t, err)
-		_, err = th.App.AddUserToChannel(th.SystemAdminUser, th.BasicChannel2)
+		_, err = th.App.AddUserToChannel(th.SystemAdminUser, th.BasicChannel2, false)
 		require.Nil(t, err)
 		props := map[string]string{}
 		props[model.DESKTOP_NOTIFY_PROP] = model.CHANNEL_NOTIFY_ALL
@@ -2847,7 +2848,7 @@ func TestRemoveChannelMember(t *testing.T) {
 			}
 		}
 
-		th.App.AddUserToChannel(th.BasicUser2, th.BasicChannel)
+		th.App.AddUserToChannel(th.BasicUser2, th.BasicChannel, false)
 		_, resp = Client.RemoveUserFromChannel(th.BasicChannel.Id, th.BasicUser2.Id)
 		CheckNoError(t, resp)
 
@@ -2878,8 +2879,8 @@ func TestRemoveChannelMember(t *testing.T) {
 	// Leave deleted channel
 	th.LoginBasic()
 	deletedChannel := th.CreatePublicChannel()
-	th.App.AddUserToChannel(th.BasicUser, deletedChannel)
-	th.App.AddUserToChannel(th.BasicUser2, deletedChannel)
+	th.App.AddUserToChannel(th.BasicUser, deletedChannel, false)
+	th.App.AddUserToChannel(th.BasicUser2, deletedChannel, false)
 
 	deletedChannel.DeleteAt = 1
 	th.App.UpdateChannel(deletedChannel)
@@ -2889,7 +2890,7 @@ func TestRemoveChannelMember(t *testing.T) {
 
 	th.LoginBasic()
 	private := th.CreatePrivateChannel()
-	th.App.AddUserToChannel(th.BasicUser2, private)
+	th.App.AddUserToChannel(th.BasicUser2, private, false)
 
 	_, resp = Client.RemoveUserFromChannel(private.Id, th.BasicUser2.Id)
 	CheckNoError(t, resp)
@@ -2899,7 +2900,7 @@ func TestRemoveChannelMember(t *testing.T) {
 	CheckForbiddenStatus(t, resp)
 
 	th.TestForSystemAdminAndLocal(t, func(t *testing.T, client *model.Client4) {
-		th.App.AddUserToChannel(th.BasicUser, private)
+		th.App.AddUserToChannel(th.BasicUser, private, false)
 		_, resp = client.RemoveUserFromChannel(private.Id, th.BasicUser.Id)
 		CheckNoError(t, resp)
 	})
@@ -3436,9 +3437,9 @@ func TestChannelMembersMinusGroupMembers(t *testing.T) {
 
 	channel := th.CreatePrivateChannel()
 
-	_, err := th.App.AddChannelMember(user1.Id, channel, "", "")
+	_, err := th.App.AddChannelMember(user1.Id, channel, app.ChannelMemberOpts{})
 	require.Nil(t, err)
-	_, err = th.App.AddChannelMember(user2.Id, channel, "", "")
+	_, err = th.App.AddChannelMember(user2.Id, channel, app.ChannelMemberOpts{})
 	require.Nil(t, err)
 
 	channel.GroupConstrained = model.NewBool(true)
diff --git a/api4/post_test.go b/api4/post_test.go
index e045b3207d..1ee10fb714 100644
--- a/api4/post_test.go
+++ b/api4/post_test.go
@@ -540,7 +540,7 @@ func TestCreatePostSendOutOfChannelMentions(t *testing.T) {
 
 	inChannelUser := th.CreateUser()
 	th.LinkUserToTeam(inChannelUser, th.BasicTeam)
-	th.App.AddUserToChannel(inChannelUser, th.BasicChannel)
+	th.App.AddUserToChannel(inChannelUser, th.BasicChannel, false)
 
 	post1 := &model.Post{ChannelId: th.BasicChannel.Id, Message: "@" + inChannelUser.Username}
 	_, resp := Client.CreatePost(post1)
@@ -1997,7 +1997,7 @@ func TestDeletePost(t *testing.T) {
 func TestDeletePostMessage(t *testing.T) {
 	th := Setup(t).InitBasic()
 	th.LinkUserToTeam(th.SystemAdminUser, th.BasicTeam)
-	th.App.AddUserToChannel(th.SystemAdminUser, th.BasicChannel)
+	th.App.AddUserToChannel(th.SystemAdminUser, th.BasicChannel, false)
 
 	defer th.TearDown()
 
@@ -2312,8 +2312,8 @@ func TestSearchPostsFromUser(t *testing.T) {
 	th.LoginTeamAdmin()
 	user := th.CreateUser()
 	th.LinkUserToTeam(user, th.BasicTeam)
-	th.App.AddUserToChannel(user, th.BasicChannel)
-	th.App.AddUserToChannel(user, th.BasicChannel2)
+	th.App.AddUserToChannel(user, th.BasicChannel, false)
+	th.App.AddUserToChannel(user, th.BasicChannel2, false)
 
 	message := "sgtitlereview with space"
 	_ = th.CreateMessagePost(message)
diff --git a/api4/user_test.go b/api4/user_test.go
index ee1f6c376d..e637e20063 100644
--- a/api4/user_test.go
+++ b/api4/user_test.go
@@ -381,7 +381,7 @@ func TestCreateUserWebSocketEvent(t *testing.T) {
 		_, _, err = th.App.AddUserToTeam(th.BasicTeam.Id, guest.Id, "")
 		require.Nil(t, err)
 
-		_, err = th.App.AddUserToChannel(guest, th.BasicChannel)
+		_, err = th.App.AddUserToChannel(guest, th.BasicChannel, false)
 		require.Nil(t, err)
 
 		guestClient := th.CreateClient()
@@ -5151,11 +5151,11 @@ func TestGetKnownUsers(t *testing.T) {
 	th.LinkUserToTeam(u3, t2)
 	th.LinkUserToTeam(u4, t3)
 
-	th.App.AddUserToChannel(u1, c1)
-	th.App.AddUserToChannel(u1, c2)
-	th.App.AddUserToChannel(u2, c1)
-	th.App.AddUserToChannel(u3, c2)
-	th.App.AddUserToChannel(u4, c3)
+	th.App.AddUserToChannel(u1, c1, false)
+	th.App.AddUserToChannel(u1, c2, false)
+	th.App.AddUserToChannel(u2, c1, false)
+	th.App.AddUserToChannel(u3, c2, false)
+	th.App.AddUserToChannel(u4, c3, false)
 
 	t.Run("get know users sharing no channels", func(t *testing.T) {
 		_, _ = th.Client.Login(u4.Email, u4.Password)
diff --git a/app/app_iface.go b/app/app_iface.go
index 27a25b05af..acfed49d46 100644
--- a/app/app_iface.go
+++ b/app/app_iface.go
@@ -42,12 +42,16 @@ type AppIface interface {
 	ListAutocompleteCommands(teamID string, T i18n.TranslateFunc) ([]*model.Command, *model.AppError)
 	// @openTracingParams teamID, skipSlackParsing
 	CreateCommandPost(post *model.Post, teamID string, response *model.CommandResponse, skipSlackParsing bool) (*model.Post, *model.AppError)
+	// AddChannelMember adds a user to a channel. It is a wrapper over AddUserToChannel.
+	AddChannelMember(userID string, channel *model.Channel, opts ChannelMemberOpts) (*model.ChannelMember, *model.AppError)
 	// AddCursorIdsForPostList adds NextPostId and PrevPostId as cursor to the PostList.
 	// The conditional blocks ensure that it sets those cursor IDs immediately as afterPost, beforePost or empty,
 	// and only query to database whenever necessary.
 	AddCursorIdsForPostList(originalList *model.PostList, afterPost, beforePost string, since int64, page, perPage int, collapsedThreads bool)
 	// AddPublicKey will add plugin public key to the config. Overwrites the previous file
 	AddPublicKey(name string, key io.Reader) *model.AppError
+	// AddUserToChannel adds a user to a given channel.
+	AddUserToChannel(user *model.User, channel *model.Channel, skipTeamMemberIntegrityCheck bool) (*model.ChannelMember, *model.AppError)
 	// Caller must close the first return value
 	FileReader(path string) (filestore.ReadCloseSeeker, *model.AppError)
 	// ChannelMembersMinusGroupMembers returns the set of users in the given channel minus the set of users in the given
@@ -359,7 +363,6 @@ type AppIface interface {
 	AcceptLanguage() string
 	AccountMigration() einterfaces.AccountMigrationInterface
 	ActivateMfa(userID, token string) *model.AppError
-	AddChannelMember(userID string, channel *model.Channel, userRequestorId string, postRootId string) (*model.ChannelMember, *model.AppError)
 	AddConfigListener(listener func(*model.Config, *model.Config)) string
 	AddDirectChannels(teamID string, user *model.User) *model.AppError
 	AddLdapPrivateCertificate(fileData *multipart.FileHeader) *model.AppError
@@ -375,7 +378,6 @@ type AppIface interface {
 	AddTeamMemberByInviteId(inviteId, userID string) (*model.TeamMember, *model.AppError)
 	AddTeamMemberByToken(userID, tokenID string) (*model.TeamMember, *model.AppError)
 	AddTeamMembers(teamID string, userIDs []string, userRequestorId string, graceful bool) ([]*model.TeamMemberWithError, *model.AppError)
-	AddUserToChannel(user *model.User, channel *model.Channel) (*model.ChannelMember, *model.AppError)
 	AddUserToTeam(teamID string, userID string, userRequestorId string) (*model.Team, *model.TeamMember, *model.AppError)
 	AddUserToTeamByInviteId(inviteId string, userID string) (*model.Team, *model.TeamMember, *model.AppError)
 	AddUserToTeamByTeamId(teamID string, user *model.User) *model.AppError
diff --git a/app/channel.go b/app/channel.go
index 40839e81b9..605d28c96c 100644
--- a/app/channel.go
+++ b/app/channel.go
@@ -15,7 +15,6 @@ import (
 	"github.com/mattermost/mattermost-server/v5/shared/i18n"
 	"github.com/mattermost/mattermost-server/v5/shared/mlog"
 	"github.com/mattermost/mattermost-server/v5/store"
-	"github.com/mattermost/mattermost-server/v5/store/sqlstore"
 	"github.com/mattermost/mattermost-server/v5/utils"
 )
 
@@ -1372,24 +1371,23 @@ func (a *App) addUserToChannel(user *model.User, channel *model.Channel) (*model
 	return newMember, nil
 }
 
-func (a *App) AddUserToChannel(user *model.User, channel *model.Channel) (*model.ChannelMember, *model.AppError) {
-	// We have to query master here because this is called during LDAP sync from:
-	// a.createDefaultChannelMemberships -> a.AddTeamMember -> a.AddChannelMember
-	// So we get a teamMember right after adding a team member which leads to a failure.
-	// TODO: pass the team member to this method.
-	teamMember, nErr := a.Srv().Store.Team().GetMember(sqlstore.WithMaster(context.Background()), channel.TeamId, user.Id)
-	if nErr != nil {
-		var nfErr *store.ErrNotFound
-		switch {
-		case errors.As(nErr, &nfErr):
-			return nil, model.NewAppError("AddUserToChannel", "app.team.get_member.missing.app_error", nil, nfErr.Error(), http.StatusNotFound)
-		default:
-			return nil, model.NewAppError("AddUserToChannel", "app.team.get_member.app_error", nil, nErr.Error(), http.StatusInternalServerError)
+// AddUserToChannel adds a user to a given channel.
+func (a *App) AddUserToChannel(user *model.User, channel *model.Channel, skipTeamMemberIntegrityCheck bool) (*model.ChannelMember, *model.AppError) {
+	if !skipTeamMemberIntegrityCheck {
+		teamMember, nErr := a.Srv().Store.Team().GetMember(context.Background(), channel.TeamId, user.Id)
+		if nErr != nil {
+			var nfErr *store.ErrNotFound
+			switch {
+			case errors.As(nErr, &nfErr):
+				return nil, model.NewAppError("AddUserToChannel", "app.team.get_member.missing.app_error", nil, nfErr.Error(), http.StatusNotFound)
+			default:
+				return nil, model.NewAppError("AddUserToChannel", "app.team.get_member.app_error", nil, nErr.Error(), http.StatusInternalServerError)
+			}
 		}
-	}
 
-	if teamMember.DeleteAt > 0 {
-		return nil, model.NewAppError("AddUserToChannel", "api.channel.add_user.to.channel.failed.deleted.app_error", nil, "", http.StatusBadRequest)
+		if teamMember.DeleteAt > 0 {
+			return nil, model.NewAppError("AddUserToChannel", "api.channel.add_user.to.channel.failed.deleted.app_error", nil, "", http.StatusBadRequest)
+		}
 	}
 
 	newMember, err := a.addUserToChannel(user, channel)
@@ -1405,7 +1403,18 @@ func (a *App) AddUserToChannel(user *model.User, channel *model.Channel) (*model
 	return newMember, nil
 }
 
-func (a *App) AddChannelMember(userID string, channel *model.Channel, userRequestorId string, postRootId string) (*model.ChannelMember, *model.AppError) {
+type ChannelMemberOpts struct {
+	UserRequestorID string
+	PostRootID      string
+	// SkipTeamMemberIntegrityCheck is used to indicate whether it should be checked
+	// that a user has already been removed from that team or not.
+	// This is useful to avoid in scenarios when we just added the team member,
+	// and thereby know that there is no need to check this.
+	SkipTeamMemberIntegrityCheck bool
+}
+
+// AddChannelMember adds a user to a channel. It is a wrapper over AddUserToChannel.
+func (a *App) AddChannelMember(userID string, channel *model.Channel, opts ChannelMemberOpts) (*model.ChannelMember, *model.AppError) {
 	if member, err := a.Srv().Store.Channel().GetMember(context.Background(), channel.Id, userID); err != nil {
 		var nfErr *store.ErrNotFound
 		if !errors.As(err, &nfErr) {
@@ -1423,13 +1432,13 @@ func (a *App) AddChannelMember(userID string, channel *model.Channel, userReques
 	}
 
 	var userRequestor *model.User
-	if userRequestorId != "" {
-		if userRequestor, err = a.GetUser(userRequestorId); err != nil {
+	if opts.UserRequestorID != "" {
+		if userRequestor, err = a.GetUser(opts.UserRequestorID); err != nil {
 			return nil, err
 		}
 	}
 
-	cm, err := a.AddUserToChannel(user, channel)
+	cm, err := a.AddUserToChannel(user, channel, opts.SkipTeamMemberIntegrityCheck)
 	if err != nil {
 		return nil, err
 	}
@@ -1444,11 +1453,11 @@ func (a *App) AddChannelMember(userID string, channel *model.Channel, userReques
 		})
 	}
 
-	if userRequestorId == "" || userID == userRequestorId {
+	if opts.UserRequestorID == "" || userID == opts.UserRequestorID {
 		a.postJoinChannelMessage(user, channel)
 	} else {
 		a.Srv().Go(func() {
-			a.PostAddToChannelMessage(userRequestor, user, channel, postRootId)
+			a.PostAddToChannelMessage(userRequestor, user, channel, opts.PostRootID)
 		})
 	}
 
@@ -1938,7 +1947,7 @@ func (a *App) JoinChannel(channel *model.Channel, userID string) *model.AppError
 		return model.NewAppError("JoinChannel", "api.channel.join_channel.permissions.app_error", nil, "", http.StatusBadRequest)
 	}
 
-	cm, err := a.AddUserToChannel(user, channel)
+	cm, err := a.AddUserToChannel(user, channel, false)
 	if err != nil {
 		return err
 	}
diff --git a/app/channel_test.go b/app/channel_test.go
index d83299509e..0ce6e81af2 100644
--- a/app/channel_test.go
+++ b/app/channel_test.go
@@ -87,7 +87,7 @@ func TestRemoveAllDeactivatedMembersFromChannel(t *testing.T) {
 	deacivatedUser := th.CreateUser()
 	_, _, err = th.App.AddUserToTeam(team.Id, deacivatedUser.Id, "")
 	require.Nil(t, err)
-	_, err = th.App.AddUserToChannel(deacivatedUser, channel)
+	_, err = th.App.AddUserToChannel(deacivatedUser, channel, false)
 	require.Nil(t, err)
 	channelMembers, err := th.App.GetChannelMembersPage(channel.Id, 0, 10000000)
 	require.Nil(t, err)
@@ -127,10 +127,10 @@ func TestMoveChannel(t *testing.T) {
 		_, _, err = th.App.AddUserToTeam(targetTeam.Id, th.BasicUser.Id, "")
 		require.Nil(t, err)
 
-		_, err = th.App.AddUserToChannel(th.BasicUser, channel1)
+		_, err = th.App.AddUserToChannel(th.BasicUser, channel1, false)
 		require.Nil(t, err)
 
-		_, err = th.App.AddUserToChannel(th.BasicUser2, channel1)
+		_, err = th.App.AddUserToChannel(th.BasicUser2, channel1, false)
 		require.Nil(t, err)
 
 		err = th.App.MoveChannel(targetTeam, channel1, th.BasicUser)
@@ -150,10 +150,10 @@ func TestMoveChannel(t *testing.T) {
 
 		_, _, err = th.App.AddUserToTeam(sourceTeam.Id, deacivatedUser.Id, "")
 		require.Nil(t, err)
-		_, err = th.App.AddUserToChannel(th.BasicUser, channel2)
+		_, err = th.App.AddUserToChannel(th.BasicUser, channel2, false)
 		require.Nil(t, err)
 
-		_, err = th.App.AddUserToChannel(deacivatedUser, channel2)
+		_, err = th.App.AddUserToChannel(deacivatedUser, channel2, false)
 		require.Nil(t, err)
 
 		_, err = th.App.UpdateActive(deacivatedUser, false)
@@ -241,9 +241,9 @@ func TestRemoveUsersFromChannelNotMemberOfTeam(t *testing.T) {
 	_, _, err = th.App.AddUserToTeam(team.Id, th.BasicUser2.Id, "")
 	require.Nil(t, err)
 
-	_, err = th.App.AddUserToChannel(th.BasicUser, channel1)
+	_, err = th.App.AddUserToChannel(th.BasicUser, channel1, false)
 	require.Nil(t, err)
-	_, err = th.App.AddUserToChannel(th.BasicUser2, channel1)
+	_, err = th.App.AddUserToChannel(th.BasicUser2, channel1, false)
 	require.Nil(t, err)
 
 	err = th.App.RemoveUsersFromChannelNotMemberOfTeam(th.SystemAdminUser, channel1, team2)
@@ -495,7 +495,7 @@ func TestAddUserToChannelCreatesChannelMemberHistoryRecord(t *testing.T) {
 
 	channel := th.createChannel(th.BasicTeam, model.CHANNEL_OPEN)
 
-	_, err = th.App.AddUserToChannel(user, channel)
+	_, err = th.App.AddUserToChannel(user, channel, false)
 	require.Nil(t, err, "Failed to add user to channel.")
 
 	// there should be a ChannelMemberHistory record for the user
@@ -581,9 +581,8 @@ func TestAddChannelMemberNoUserRequestor(t *testing.T) {
 	groupUserIds = append(groupUserIds, user.Id)
 
 	channel := th.createChannel(th.BasicTeam, model.CHANNEL_OPEN)
-	userRequestorId := ""
-	postRootId := ""
-	_, err = th.App.AddChannelMember(user.Id, channel, userRequestorId, postRootId)
+
+	_, err = th.App.AddChannelMember(user.Id, channel, ChannelMemberOpts{})
 	require.Nil(t, err, "Failed to add user to channel.")
 
 	// there should be a ChannelMemberHistory record for the user
@@ -952,9 +951,7 @@ func TestGetChannelMembersTimezones(t *testing.T) {
 	th := Setup(t).InitBasic()
 	defer th.TearDown()
 
-	userRequestorId := ""
-	postRootId := ""
-	_, err := th.App.AddChannelMember(th.BasicUser2.Id, th.BasicChannel, userRequestorId, postRootId)
+	_, err := th.App.AddChannelMember(th.BasicUser2.Id, th.BasicChannel, ChannelMemberOpts{})
 	require.Nil(t, err, "Failed to add user to channel.")
 
 	user := th.BasicUser
@@ -968,14 +965,14 @@ func TestGetChannelMembersTimezones(t *testing.T) {
 
 	user3 := model.User{Email: strings.ToLower(model.NewId()) + "success+test@example.com", Nickname: "Darth Vader", Username: "vader" + model.NewId(), Password: "passwd1", AuthService: ""}
 	ruser, _ := th.App.CreateUser(&user3)
-	th.App.AddUserToChannel(ruser, th.BasicChannel)
+	th.App.AddUserToChannel(ruser, th.BasicChannel, false)
 
 	ruser.Timezone["automaticTimezone"] = "NoWhere/Island"
 	th.App.UpdateUser(ruser, false)
 
 	user4 := model.User{Email: strings.ToLower(model.NewId()) + "success+test@example.com", Nickname: "Darth Vader", Username: "vader" + model.NewId(), Password: "passwd1", AuthService: ""}
 	ruser, _ = th.App.CreateUser(&user4)
-	th.App.AddUserToChannel(ruser, th.BasicChannel)
+	th.App.AddUserToChannel(ruser, th.BasicChannel, false)
 
 	timezones, err := th.App.GetChannelMembersTimezones(th.BasicChannel.Id)
 	require.Nil(t, err, "Failed to get the timezones for a channel.")
@@ -1101,7 +1098,7 @@ func TestUpdateChannelMemberRolesChangingGuest(t *testing.T) {
 		_, _, err := th.App.AddUserToTeam(th.BasicTeam.Id, ruser.Id, "")
 		require.Nil(t, err)
 
-		_, err = th.App.AddUserToChannel(ruser, th.BasicChannel)
+		_, err = th.App.AddUserToChannel(ruser, th.BasicChannel, false)
 		require.Nil(t, err)
 
 		_, err = th.App.UpdateChannelMemberRoles(th.BasicChannel.Id, ruser.Id, "channel_user")
@@ -1115,7 +1112,7 @@ func TestUpdateChannelMemberRolesChangingGuest(t *testing.T) {
 		_, _, err := th.App.AddUserToTeam(th.BasicTeam.Id, ruser.Id, "")
 		require.Nil(t, err)
 
-		_, err = th.App.AddUserToChannel(ruser, th.BasicChannel)
+		_, err = th.App.AddUserToChannel(ruser, th.BasicChannel, false)
 		require.Nil(t, err)
 
 		_, err = th.App.UpdateChannelMemberRoles(th.BasicChannel.Id, ruser.Id, "channel_guest")
@@ -1129,7 +1126,7 @@ func TestUpdateChannelMemberRolesChangingGuest(t *testing.T) {
 		_, _, err := th.App.AddUserToTeam(th.BasicTeam.Id, ruser.Id, "")
 		require.Nil(t, err)
 
-		_, err = th.App.AddUserToChannel(ruser, th.BasicChannel)
+		_, err = th.App.AddUserToChannel(ruser, th.BasicChannel, false)
 		require.Nil(t, err)
 
 		_, err = th.App.UpdateChannelMemberRoles(th.BasicChannel.Id, ruser.Id, "channel_user channel_admin")
@@ -1143,7 +1140,7 @@ func TestUpdateChannelMemberRolesChangingGuest(t *testing.T) {
 		_, _, err := th.App.AddUserToTeam(th.BasicTeam.Id, ruser.Id, "")
 		require.Nil(t, err)
 
-		_, err = th.App.AddUserToChannel(ruser, th.BasicChannel)
+		_, err = th.App.AddUserToChannel(ruser, th.BasicChannel, false)
 		require.Nil(t, err)
 
 		_, err = th.App.CreateRole(&model.Role{Name: "custom", DisplayName: "custom", Description: "custom"})
@@ -1160,7 +1157,7 @@ func TestUpdateChannelMemberRolesChangingGuest(t *testing.T) {
 		_, _, err := th.App.AddUserToTeam(th.BasicTeam.Id, ruser.Id, "")
 		require.Nil(t, err)
 
-		_, err = th.App.AddUserToChannel(ruser, th.BasicChannel)
+		_, err = th.App.AddUserToChannel(ruser, th.BasicChannel, false)
 		require.Nil(t, err)
 
 		_, err = th.App.UpdateChannelMemberRoles(th.BasicChannel.Id, ruser.Id, "channel_guest channel_user")
@@ -1205,9 +1202,9 @@ func TestSearchChannelsForUser(t *testing.T) {
 	}()
 
 	// add user to test-dev-1 and dev3
-	_, err = th.App.AddUserToChannel(th.BasicUser, c1)
+	_, err = th.App.AddUserToChannel(th.BasicUser, c1, false)
 	require.Nil(t, err)
-	_, err = th.App.AddUserToChannel(th.BasicUser, c3)
+	_, err = th.App.AddUserToChannel(th.BasicUser, c3, false)
 	require.Nil(t, err)
 
 	searchAndCheck := func(t *testing.T, term string, expectedDisplayNames []string) {
@@ -1231,7 +1228,7 @@ func TestSearchChannelsForUser(t *testing.T) {
 	})
 
 	t.Run("After adding user to test-dev-2, search for dev, the three channels should be returned", func(t *testing.T) {
-		_, err = th.App.AddUserToChannel(th.BasicUser, c2)
+		_, err = th.App.AddUserToChannel(th.BasicUser, c2, false)
 		require.Nil(t, err)
 
 		searchAndCheck(t, "dev", []string{"test-dev-1", "test-dev-2", "dev-3"})
@@ -1332,7 +1329,7 @@ func TestMarkChannelAsUnreadFromPost(t *testing.T) {
 
 	t.Run("Unread with mentions", func(t *testing.T) {
 		c2 := th.CreateChannel(th.BasicTeam)
-		_, err := th.App.AddUserToChannel(u2, c2)
+		_, err := th.App.AddUserToChannel(u2, c2, false)
 		require.Nil(t, err)
 
 		p4, err := th.App.CreatePost(&model.Post{
@@ -1445,7 +1442,7 @@ func TestAddUserToChannel(t *testing.T) {
 	require.Nil(t, err)
 
 	// Should allow a bot to be added to a public group synced channel
-	_, err = th.App.AddUserToChannel(botUser, th.BasicChannel)
+	_, err = th.App.AddUserToChannel(botUser, th.BasicChannel, false)
 	require.Nil(t, err)
 
 	// verify user was added as an admin
@@ -1466,11 +1463,11 @@ func TestAddUserToChannel(t *testing.T) {
 	require.Nil(t, err)
 
 	// Should allow a group synced user to be added to a group synced private channel
-	_, err = th.App.AddUserToChannel(ruser1, privateChannel)
+	_, err = th.App.AddUserToChannel(ruser1, privateChannel, false)
 	require.Nil(t, err)
 
 	// Should allow a bot to be added to a private group synced channel
-	_, err = th.App.AddUserToChannel(botUser, privateChannel)
+	_, err = th.App.AddUserToChannel(botUser, privateChannel, false)
 	require.Nil(t, err)
 }
 
@@ -1491,9 +1488,9 @@ func TestRemoveUserFromChannel(t *testing.T) {
 
 	privateChannel := th.CreatePrivateChannel(th.BasicTeam)
 
-	_, err := th.App.AddUserToChannel(ruser, privateChannel)
+	_, err := th.App.AddUserToChannel(ruser, privateChannel, false)
 	require.Nil(t, err)
-	_, err = th.App.AddUserToChannel(botUser, privateChannel)
+	_, err = th.App.AddUserToChannel(botUser, privateChannel, false)
 	require.Nil(t, err)
 
 	group := th.CreateGroup()
diff --git a/app/helper_test.go b/app/helper_test.go
index 9954adc898..28ee5c06df 100644
--- a/app/helper_test.go
+++ b/app/helper_test.go
@@ -422,7 +422,7 @@ func (th *TestHelper) RemoveUserFromTeam(user *model.User, team *model.Team) {
 func (th *TestHelper) AddUserToChannel(user *model.User, channel *model.Channel) *model.ChannelMember {
 	utils.DisableDebugLogForTest()
 
-	member, err := th.App.AddUserToChannel(user, channel)
+	member, err := th.App.AddUserToChannel(user, channel, false)
 	if err != nil {
 		panic(err)
 	}
diff --git a/app/notification_test.go b/app/notification_test.go
index 668820ff00..d373a35232 100644
--- a/app/notification_test.go
+++ b/app/notification_test.go
@@ -19,7 +19,7 @@ func TestSendNotifications(t *testing.T) {
 	th := Setup(t).InitBasic()
 	defer th.TearDown()
 
-	th.App.AddUserToChannel(th.BasicUser2, th.BasicChannel)
+	th.App.AddUserToChannel(th.BasicUser2, th.BasicChannel, false)
 
 	post1, appErr := th.App.CreatePostMissingChannel(&model.Post{
 		UserId:    th.BasicUser.Id,
@@ -126,7 +126,7 @@ func TestSendNotificationsWithManyUsers(t *testing.T) {
 	for i := 0; i < 10; i++ {
 		user := th.CreateUser()
 		th.LinkUserToTeam(user, th.BasicTeam)
-		th.App.AddUserToChannel(user, th.BasicChannel)
+		th.App.AddUserToChannel(user, th.BasicChannel, false)
 		users = append(users, user)
 	}
 
@@ -217,9 +217,9 @@ func TestFilterOutOfChannelMentions(t *testing.T) {
 	th.LinkUserToTeam(user3, th.BasicTeam)
 	th.LinkUserToTeam(user4, th.BasicTeam)
 	th.LinkUserToTeam(guest, th.BasicTeam)
-	th.App.AddUserToChannel(guest, channel)
-	th.App.AddUserToChannel(user4, guestAndUser4Channel)
-	th.App.AddUserToChannel(guest, guestAndUser4Channel)
+	th.App.AddUserToChannel(guest, channel, false)
+	th.App.AddUserToChannel(user4, guestAndUser4Channel, false)
+	th.App.AddUserToChannel(guest, guestAndUser4Channel, false)
 
 	t.Run("should return users not in the channel", func(t *testing.T) {
 		post := &model.Post{}
@@ -2420,13 +2420,13 @@ func TestInsertGroupMentions(t *testing.T) {
 
 	groupChannelMember := th.CreateUser()
 	th.LinkUserToTeam(groupChannelMember, team)
-	th.App.AddUserToChannel(groupChannelMember, channel)
+	th.App.AddUserToChannel(groupChannelMember, channel, false)
 	_, err = th.App.UpsertGroupMember(group.Id, groupChannelMember.Id)
 	require.Nil(t, err)
 
 	nonGroupChannelMember := th.CreateUser()
 	th.LinkUserToTeam(nonGroupChannelMember, team)
-	th.App.AddUserToChannel(nonGroupChannelMember, channel)
+	th.App.AddUserToChannel(nonGroupChannelMember, channel, false)
 
 	nonChannelGroupMember := th.CreateUser()
 	th.LinkUserToTeam(nonChannelGroupMember, team)
diff --git a/app/opentracing/opentracing_layer.go b/app/opentracing/opentracing_layer.go
index f9473d0262..79e6730653 100644
--- a/app/opentracing/opentracing_layer.go
+++ b/app/opentracing/opentracing_layer.go
@@ -94,7 +94,7 @@ func (a *OpenTracingAppLayer) ActivateMfa(userID string, token string) *model.Ap
 	return resultVar0
 }
 
-func (a *OpenTracingAppLayer) AddChannelMember(userID string, channel *model.Channel, userRequestorId string, postRootId string) (*model.ChannelMember, *model.AppError) {
+func (a *OpenTracingAppLayer) AddChannelMember(userID string, channel *model.Channel, opts app.ChannelMemberOpts) (*model.ChannelMember, *model.AppError) {
 	origCtx := a.ctx
 	span, newCtx := tracing.StartSpanWithParentByContext(a.ctx, "app.AddChannelMember")
 
@@ -106,7 +106,7 @@ func (a *OpenTracingAppLayer) AddChannelMember(userID string, channel *model.Cha
 	}()
 
 	defer span.Finish()
-	resultVar0, resultVar1 := a.app.AddChannelMember(userID, channel, userRequestorId, postRootId)
+	resultVar0, resultVar1 := a.app.AddChannelMember(userID, channel, opts)
 
 	if resultVar1 != nil {
 		span.LogFields(spanlog.Error(resultVar1))
@@ -457,7 +457,7 @@ func (a *OpenTracingAppLayer) AddTeamMembers(teamID string, userIDs []string, us
 	return resultVar0, resultVar1
 }
 
-func (a *OpenTracingAppLayer) AddUserToChannel(user *model.User, channel *model.Channel) (*model.ChannelMember, *model.AppError) {
+func (a *OpenTracingAppLayer) AddUserToChannel(user *model.User, channel *model.Channel, skipTeamMemberIntegrityCheck bool) (*model.ChannelMember, *model.AppError) {
 	origCtx := a.ctx
 	span, newCtx := tracing.StartSpanWithParentByContext(a.ctx, "app.AddUserToChannel")
 
@@ -469,7 +469,7 @@ func (a *OpenTracingAppLayer) AddUserToChannel(user *model.User, channel *model.
 	}()
 
 	defer span.Finish()
-	resultVar0, resultVar1 := a.app.AddUserToChannel(user, channel)
+	resultVar0, resultVar1 := a.app.AddUserToChannel(user, channel, skipTeamMemberIntegrityCheck)
 
 	if resultVar1 != nil {
 		span.LogFields(spanlog.Error(resultVar1))
diff --git a/app/plugin_api.go b/app/plugin_api.go
index 503cd3fd95..53624f61a1 100644
--- a/app/plugin_api.go
+++ b/app/plugin_api.go
@@ -478,27 +478,27 @@ func (api *PluginAPI) SearchPostsInTeamForUser(teamID string, userID string, sea
 }
 
 func (api *PluginAPI) AddChannelMember(channelID, userID string) (*model.ChannelMember, *model.AppError) {
-	// For now, don't allow overriding these via the plugin API.
-	userRequestorId := ""
-	postRootId := ""
-
 	channel, err := api.GetChannel(channelID)
 	if err != nil {
 		return nil, err
 	}
 
-	return api.app.AddChannelMember(userID, channel, userRequestorId, postRootId)
+	return api.app.AddChannelMember(userID, channel, ChannelMemberOpts{
+		// For now, don't allow overriding these via the plugin API.
+		UserRequestorID: "",
+		PostRootID:      "",
+	})
 }
 
-func (api *PluginAPI) AddUserToChannel(channelID, userID, asUserId string) (*model.ChannelMember, *model.AppError) {
-	postRootId := ""
-
+func (api *PluginAPI) AddUserToChannel(channelID, userID, asUserID string) (*model.ChannelMember, *model.AppError) {
 	channel, err := api.GetChannel(channelID)
 	if err != nil {
 		return nil, err
 	}
 
-	return api.app.AddChannelMember(userID, channel, asUserId, postRootId)
+	return api.app.AddChannelMember(userID, channel, ChannelMemberOpts{
+		UserRequestorID: asUserID,
+	})
 }
 
 func (api *PluginAPI) GetChannelMember(channelID, userID string) (*model.ChannelMember, *model.AppError) {
diff --git a/app/post_test.go b/app/post_test.go
index 6832f790a5..666da41922 100644
--- a/app/post_test.go
+++ b/app/post_test.go
@@ -338,7 +338,7 @@ func TestPostReplyToPostWhereRootPosterLeftChannel(t *testing.T) {
 	userNotInChannel := th.BasicUser
 	rootPost := th.BasicPost
 
-	_, err := th.App.AddUserToChannel(userInChannel, channel)
+	_, err := th.App.AddUserToChannel(userInChannel, channel, false)
 	require.Nil(t, err)
 
 	err = th.App.RemoveUserFromChannel(userNotInChannel.Id, "", channel)
@@ -421,7 +421,7 @@ func TestPostChannelMentions(t *testing.T) {
 	require.Nil(t, err)
 	defer th.App.PermanentDeleteChannel(channelToMention)
 
-	_, err = th.App.AddUserToChannel(user, channel)
+	_, err = th.App.AddUserToChannel(user, channel, false)
 	require.Nil(t, err)
 
 	post := &model.Post{
diff --git a/app/slashcommands/command_invite.go b/app/slashcommands/command_invite.go
index c7c289caed..b8f54263ea 100644
--- a/app/slashcommands/command_invite.go
+++ b/app/slashcommands/command_invite.go
@@ -140,7 +140,9 @@ func (*InviteProvider) DoCommand(a *app.App, args *model.CommandArgs, message st
 		}
 	}
 
-	if _, err := a.AddChannelMember(userProfile.Id, channelToJoin, args.UserId, ""); err != nil {
+	if _, err := a.AddChannelMember(userProfile.Id, channelToJoin, app.ChannelMemberOpts{
+		UserRequestorID: args.UserId,
+	}); err != nil {
 		var text string
 		if err.Id == "api.channel.add_members.user_denied" {
 			text = args.T("api.command_invite.group_constrained_user_denied")
diff --git a/app/slashcommands/command_invite_test.go b/app/slashcommands/command_invite_test.go
index e451d178e0..d3f84cc7cd 100644
--- a/app/slashcommands/command_invite_test.go
+++ b/app/slashcommands/command_invite_test.go
@@ -9,6 +9,7 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
+	"github.com/mattermost/mattermost-server/v5/app"
 	"github.com/mattermost/mattermost-server/v5/model"
 )
 
@@ -72,7 +73,7 @@ func TestInviteProvider(t *testing.T) {
 	deactivatedUserPublicChannel := "@" + deactivatedUser.Username + " ~" + channel.Name
 
 	groupChannel := th.createChannel(th.BasicTeam, model.CHANNEL_PRIVATE)
-	_, err = th.App.AddChannelMember(th.BasicUser.Id, groupChannel, "", "")
+	_, err = th.App.AddChannelMember(th.BasicUser.Id, groupChannel, app.ChannelMemberOpts{})
 	require.Nil(t, err)
 	groupChannel.GroupConstrained = model.NewBool(true)
 	groupChannel, _ = th.App.UpdateChannel(groupChannel)
diff --git a/app/slashcommands/command_leave_test.go b/app/slashcommands/command_leave_test.go
index a71f8d5326..54cd0e48d1 100644
--- a/app/slashcommands/command_leave_test.go
+++ b/app/slashcommands/command_leave_test.go
@@ -41,11 +41,11 @@ func TestLeaveProviderDoCommand(t *testing.T) {
 	guest := th.createGuest()
 
 	th.App.AddUserToTeam(th.BasicTeam.Id, th.BasicUser.Id, th.BasicUser.Id)
-	th.App.AddUserToChannel(th.BasicUser, publicChannel)
-	th.App.AddUserToChannel(th.BasicUser, privateChannel)
+	th.App.AddUserToChannel(th.BasicUser, publicChannel, false)
+	th.App.AddUserToChannel(th.BasicUser, privateChannel, false)
 	th.App.AddUserToTeam(th.BasicTeam.Id, guest.Id, guest.Id)
-	th.App.AddUserToChannel(guest, publicChannel)
-	th.App.AddUserToChannel(guest, defaultChannel)
+	th.App.AddUserToChannel(guest, publicChannel, false)
+	th.App.AddUserToChannel(guest, defaultChannel, false)
 
 	t.Run("Should error when no Channel ID in args", func(t *testing.T) {
 		args := &model.CommandArgs{
diff --git a/app/slashcommands/command_remove_test.go b/app/slashcommands/command_remove_test.go
index eeb68bfd8c..1e8a68c19d 100644
--- a/app/slashcommands/command_remove_test.go
+++ b/app/slashcommands/command_remove_test.go
@@ -35,8 +35,8 @@ func TestRemoveProviderDoCommand(t *testing.T) {
 
 	targetUser := th.createUser()
 	th.App.AddUserToTeam(th.BasicTeam.Id, targetUser.Id, targetUser.Id)
-	th.App.AddUserToChannel(targetUser, publicChannel)
-	th.App.AddUserToChannel(targetUser, privateChannel)
+	th.App.AddUserToChannel(targetUser, publicChannel, false)
+	th.App.AddUserToChannel(targetUser, privateChannel, false)
 
 	// Try a public channel *without* permission.
 	args := &model.CommandArgs{
@@ -49,7 +49,7 @@ func TestRemoveProviderDoCommand(t *testing.T) {
 	assert.Equal(t, "api.command_remove.permission.app_error", actual)
 
 	// Try a public channel *with* permission.
-	th.App.AddUserToChannel(th.BasicUser, publicChannel)
+	th.App.AddUserToChannel(th.BasicUser, publicChannel, false)
 	args = &model.CommandArgs{
 		T:         func(s string, args ...interface{}) string { return s },
 		ChannelId: publicChannel.Id,
@@ -70,7 +70,7 @@ func TestRemoveProviderDoCommand(t *testing.T) {
 	assert.Equal(t, "api.command_remove.permission.app_error", actual)
 
 	// Try a private channel *with* permission.
-	th.App.AddUserToChannel(th.BasicUser, privateChannel)
+	th.App.AddUserToChannel(th.BasicUser, privateChannel, false)
 	args = &model.CommandArgs{
 		T:         func(s string, args ...interface{}) string { return s },
 		ChannelId: privateChannel.Id,
@@ -110,7 +110,7 @@ func TestRemoveProviderDoCommand(t *testing.T) {
 	// Try a public channel with a deactivated user.
 	deactivatedUser := th.createUser()
 	th.App.AddUserToTeam(th.BasicTeam.Id, deactivatedUser.Id, deactivatedUser.Id)
-	th.App.AddUserToChannel(deactivatedUser, publicChannel)
+	th.App.AddUserToChannel(deactivatedUser, publicChannel, false)
 	th.App.UpdateActive(deactivatedUser, false)
 
 	args = &model.CommandArgs{
diff --git a/app/slashcommands/helper_test.go b/app/slashcommands/helper_test.go
index 9b0f6afc8b..404488776c 100644
--- a/app/slashcommands/helper_test.go
+++ b/app/slashcommands/helper_test.go
@@ -358,7 +358,7 @@ func (th *TestHelper) linkUserToTeam(user *model.User, team *model.Team) {
 func (th *TestHelper) addUserToChannel(user *model.User, channel *model.Channel) *model.ChannelMember {
 	utils.DisableDebugLogForTest()
 
-	member, err := th.App.AddUserToChannel(user, channel)
+	member, err := th.App.AddUserToChannel(user, channel, false)
 	if err != nil {
 		panic(err)
 	}
diff --git a/app/syncables.go b/app/syncables.go
index e3090930e3..2cda472959 100644
--- a/app/syncables.go
+++ b/app/syncables.go
@@ -52,7 +52,9 @@ func (a *App) createDefaultChannelMemberships(since int64, channelID *string) er
 			)
 		}
 
-		_, err = a.AddChannelMember(userChannel.UserID, channel, "", "")
+		_, err = a.AddChannelMember(userChannel.UserID, channel, ChannelMemberOpts{
+			SkipTeamMemberIntegrityCheck: true,
+		})
 		if err != nil {
 			if err.Id == "api.channel.add_user.to.channel.failed.deleted.app_error" {
 				a.Log().Info("Not adding user to channel because they have already left the team",
diff --git a/app/syncables_test.go b/app/syncables_test.go
index 7fee2bcece..fc9be6bdeb 100644
--- a/app/syncables_test.go
+++ b/app/syncables_test.go
@@ -262,7 +262,7 @@ func TestCreateDefaultMemberships(t *testing.T) {
 	}
 
 	// Ensure members are in channel
-	_, err = th.App.AddChannelMember(scientist1.Id, experimentsChannel, "", "")
+	_, err = th.App.AddChannelMember(scientist1.Id, experimentsChannel, ChannelMemberOpts{})
 	if err != nil {
 		t.Errorf("unable to add user to channel: %s", err.Error())
 	}
@@ -272,7 +272,7 @@ func TestCreateDefaultMemberships(t *testing.T) {
 	if err != nil {
 		t.Errorf("unable to add user to team: %s", err.Error())
 	}
-	_, err = th.App.AddChannelMember(singer1.Id, experimentsChannel, "", "")
+	_, err = th.App.AddChannelMember(singer1.Id, experimentsChannel, ChannelMemberOpts{})
 	if err != nil {
 		t.Errorf("unable to add user to channel: %s", err.Error())
 	}
@@ -388,7 +388,7 @@ func TestDeleteGroupMemberships(t *testing.T) {
 		_, err = th.App.AddTeamMember(th.BasicTeam.Id, userID)
 		require.Nil(t, err)
 
-		_, err = th.App.AddChannelMember(userID, th.BasicChannel, "", "")
+		_, err = th.App.AddChannelMember(userID, th.BasicChannel, ChannelMemberOpts{})
 		require.Nil(t, err)
 	}
 
diff --git a/app/team.go b/app/team.go
index 38bb37e42a..05b35bf12b 100644
--- a/app/team.go
+++ b/app/team.go
@@ -623,7 +623,7 @@ func (a *App) AddUserToTeamByToken(userID string, tokenID string) (*model.Team,
 		}
 
 		for _, channel := range channels {
-			_, err := a.AddUserToChannel(user, channel)
+			_, err := a.AddUserToChannel(user, channel, false)
 			if err != nil {
 				mlog.Warn("Error adding user to channel", mlog.Err(err))
 			}
diff --git a/app/user.go b/app/user.go
index fd1626d311..ca97a2b3aa 100644
--- a/app/user.go
+++ b/app/user.go
@@ -104,7 +104,7 @@ func (a *App) CreateUserWithToken(user *model.User, token *model.Token) (*model.
 
 	if token.Type == TokenTypeGuestInvitation {
 		for _, channel := range channels {
-			_, err := a.AddChannelMember(ruser.Id, channel, "", "")
+			_, err := a.AddChannelMember(ruser.Id, channel, ChannelMemberOpts{})
 			if err != nil {
 				mlog.Warn("Failed to add channel member", mlog.Err(err))
 			}
diff --git a/app/user_test.go b/app/user_test.go
index e7b6ac37c5..806e45b741 100644
--- a/app/user_test.go
+++ b/app/user_test.go
@@ -993,9 +993,9 @@ func TestGetViewUsersRestrictions(t *testing.T) {
 	team2townsquare, err := th.App.GetChannelByName("town-square", team2.Id, false)
 	require.Nil(t, err)
 
-	th.App.AddUserToChannel(user1, team1channel1)
-	th.App.AddUserToChannel(user1, team1channel2)
-	th.App.AddUserToChannel(user1, team2channel1)
+	th.App.AddUserToChannel(user1, team1channel1, false)
+	th.App.AddUserToChannel(user1, team1channel2, false)
+	th.App.AddUserToChannel(user1, team2channel1, false)
 
 	addPermission := func(role *model.Role, permission string) *model.AppError {
 		newPermissions := append(role.Permissions, permission)
diff --git a/cmd/mattermost/commands/channel.go b/cmd/mattermost/commands/channel.go
index f0d20ef50e..191383d4b6 100644
--- a/cmd/mattermost/commands/channel.go
+++ b/cmd/mattermost/commands/channel.go
@@ -311,7 +311,7 @@ func addUserToChannel(a *app.App, channel *model.Channel, user *model.User, user
 		CommandPrintErrorln("Can't find user '" + userArg + "'")
 		return
 	}
-	if _, err := a.AddUserToChannel(user, channel); err != nil {
+	if _, err := a.AddUserToChannel(user, channel, false); err != nil {
 		CommandPrintErrorln("Unable to add '" + userArg + "' from " + channel.Name + ". Error: " + err.Error())
 		return
 	}
diff --git a/migrations/helper_test.go b/migrations/helper_test.go
index 4c439c8b30..4aad6ae296 100644
--- a/migrations/helper_test.go
+++ b/migrations/helper_test.go
@@ -217,7 +217,7 @@ func (th *TestHelper) LinkUserToTeam(user *model.User, team *model.Team) {
 func (th *TestHelper) AddUserToChannel(user *model.User, channel *model.Channel) *model.ChannelMember {
 	utils.DisableDebugLogForTest()
 
-	member, err := th.App.AddUserToChannel(user, channel)
+	member, err := th.App.AddUserToChannel(user, channel, false)
 	if err != nil {
 		panic(err)
 	}
diff --git a/services/sharedchannel/mock_AppIface_test.go b/services/sharedchannel/mock_AppIface_test.go
index 645a96e2d5..96e96c81e6 100644
--- a/services/sharedchannel/mock_AppIface_test.go
+++ b/services/sharedchannel/mock_AppIface_test.go
@@ -16,13 +16,13 @@ type MockAppIface struct {
 	mock.Mock
 }
 
-// AddUserToChannel provides a mock function with given fields: user, channel
-func (_m *MockAppIface) AddUserToChannel(user *model.User, channel *model.Channel) (*model.ChannelMember, *model.AppError) {
-	ret := _m.Called(user, channel)
+// AddUserToChannel provides a mock function with given fields: user, channel, skipTeamMemberIntegrityCheck
+func (_m *MockAppIface) AddUserToChannel(user *model.User, channel *model.Channel, skipTeamMemberIntegrityCheck bool) (*model.ChannelMember, *model.AppError) {
+	ret := _m.Called(user, channel, skipTeamMemberIntegrityCheck)
 
 	var r0 *model.ChannelMember
-	if rf, ok := ret.Get(0).(func(*model.User, *model.Channel) *model.ChannelMember); ok {
-		r0 = rf(user, channel)
+	if rf, ok := ret.Get(0).(func(*model.User, *model.Channel, bool) *model.ChannelMember); ok {
+		r0 = rf(user, channel, skipTeamMemberIntegrityCheck)
 	} else {
 		if ret.Get(0) != nil {
 			r0 = ret.Get(0).(*model.ChannelMember)
@@ -30,8 +30,8 @@ func (_m *MockAppIface) AddUserToChannel(user *model.User, channel *model.Channe
 	}
 
 	var r1 *model.AppError
-	if rf, ok := ret.Get(1).(func(*model.User, *model.Channel) *model.AppError); ok {
-		r1 = rf(user, channel)
+	if rf, ok := ret.Get(1).(func(*model.User, *model.Channel, bool) *model.AppError); ok {
+		r1 = rf(user, channel, skipTeamMemberIntegrityCheck)
 	} else {
 		if ret.Get(1) != nil {
 			r1 = ret.Get(1).(*model.AppError)
diff --git a/services/sharedchannel/service.go b/services/sharedchannel/service.go
index 9bb02edddb..ebf7dfcae2 100644
--- a/services/sharedchannel/service.go
+++ b/services/sharedchannel/service.go
@@ -42,7 +42,7 @@ type AppIface interface {
 	SendEphemeralPost(userId string, post *model.Post) *model.Post
 	CreateChannelWithUser(channel *model.Channel, userId string) (*model.Channel, *model.AppError)
 	GetOrCreateDirectChannel(userId, otherUserId string, channelOptions ...model.ChannelOption) (*model.Channel, *model.AppError)
-	AddUserToChannel(user *model.User, channel *model.Channel) (*model.ChannelMember, *model.AppError)
+	AddUserToChannel(user *model.User, channel *model.Channel, skipTeamMemberIntegrityCheck bool) (*model.ChannelMember, *model.AppError)
 	AddUserToTeamByTeamId(teamId string, user *model.User) *model.AppError
 	PermanentDeleteChannel(channel *model.Channel) *model.AppError
 	CreatePost(post *model.Post, channel *model.Channel, triggerWebhooks bool, setOnline bool) (savedPost *model.Post, err *model.AppError)
diff --git a/services/sharedchannel/sync_recv.go b/services/sharedchannel/sync_recv.go
index 8e837849be..b1007cb8f9 100644
--- a/services/sharedchannel/sync_recv.go
+++ b/services/sharedchannel/sync_recv.go
@@ -222,7 +222,7 @@ func (scs *Service) upsertSyncUser(user *model.User, channel *model.Channel, rc
 	}
 
 	// add user to channel
-	if _, err := scs.app.AddUserToChannel(userSaved, channel); err != nil {
+	if _, err := scs.app.AddUserToChannel(userSaved, channel, false); err != nil {
 		return nil, fmt.Errorf("error adding sync user to ChannelMembers: %w", err)
 	}
 	return userSaved, nil
diff --git a/services/slackimport/slackimport.go b/services/slackimport/slackimport.go
index 2287ce6002..13a5ff886f 100644
--- a/services/slackimport/slackimport.go
+++ b/services/slackimport/slackimport.go
@@ -83,7 +83,7 @@ type slackComment struct {
 // Actions provides the actions that needs to be used for import slack data
 type Actions struct {
 	UpdateActive           func(*model.User, bool) (*model.User, *model.AppError)
-	AddUserToChannel       func(*model.User, *model.Channel) (*model.ChannelMember, *model.AppError)
+	AddUserToChannel       func(*model.User, *model.Channel, bool) (*model.ChannelMember, *model.AppError)
 	JoinUserToTeam         func(*model.Team, *model.User, string) (*model.TeamMember, *model.AppError)
 	CreateDirectChannel    func(string, string, ...model.ChannelOption) (*model.Channel, *model.AppError)
 	CreateGroupChannel     func([]string) (*model.Channel, *model.AppError)
@@ -535,7 +535,7 @@ func (si *SlackImporter) addSlackUsersToChannel(members []string, users map[stri
 			log.WriteString(i18n.T("api.slackimport.slack_add_channels.failed_to_add_user", map[string]interface{}{"Username": "?"}))
 			continue
 		}
-		if _, err := si.actions.AddUserToChannel(user, channel); err != nil {
+		if _, err := si.actions.AddUserToChannel(user, channel, false); err != nil {
 			log.WriteString(i18n.T("api.slackimport.slack_add_channels.failed_to_add_user", map[string]interface{}{"Username": user.Username}))
 		}
 	}