We have had a universal security group setup that is used for email distribution and permissions.
Over the past three weeks we have noticed that somehow all of the members are getting removed and the group becomes a member of itself.
We haven't been able to figure out why it's happening, but it appears to be happening in the overnight hours because I check it throughout the day and the membership is okay. When I check in first thing the next morning the changes have been made.
I have tried installing the free version of Netwrix Active Directory change reporter, but it isn't showing anything about the changes happening to that group or members of the group.