There are 3 possibilities of how AD behaves:
1) the user has a memberOf pointing to a group, but the group does not have a member attribute pointing back to the user.
2) the group has a member attribute pointing to a user, but the user does not have a memberOf attribute pointing back to the group.
3) the group has a member attribute pointing to a user, and the user has a memberOf pointing to a group
If I am seeing scenario #1 and scenario #2 happen on my enterprise system, is this indicative of a problem?
Because this conversation here:
Active Directory 2019 - did something change with how member, memberOf, and whenChanged operate?
says that the User's memberOf record is not even stored. So how would these ever be out of sync?