It seems that permissions once set in for moderators, under super mod permissions in VB, are given to users after an import who previously held moderator positions.
I have confirmed this behavior in vB3.8. Add a user to the super mod group, then edit and save their mod permissions under Show All Moderators. Now remove the user from the super mod group. The result is an orphaned record for that user in the moderator table.I just checked out my database. It turns out that VB doesn't clear old moderator permissions, even after the mod is moved to a "normal" usergroup. I confirmed by adding one of my old mods as a mod again on my VB board and, low and behold, they re-inherited their old permissions. Seems to be a VB error that the importer interprets otherwise.