Created attachment 11205 [details] reproduce For bug 56581 I was investigating quick group changes. Adding a member and quickly removing it again from a group. It looks like under some conditions group members are added to a group again even though they were removed. The problem seems to boil down to the following scenario: - Add a member to a group in a large sync from ucs transaction - After the ad connector switches to the sync to ucs part, remove the member again. This needs to happen while the ad connector is in the sync to ucs part but before the ad connector is processing the member add action originally triggered in the previous step. See the attached script to reproduce this. The ad connector log level needs to be in debug mode. You might need to run it a few times and check the group in the ad. Sometimes the members got out of sync?