AD Sync tool is deleting a groupmembership in Sophos Central

when I run the AD sync a specific server in Sophos Central is moved from AD group to no group. However, the group is available in Central and I can manually move the server back there. But a sync deletes this assignment again. In AD, the server can be found in the appropriate group. In the preview of the sync tool no change is shown.
Maybe someone knows the solution.

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[edited by: GlennSen at 6:15 AM (GMT -7) on 8 Apr 2022]