I know any edits I make say "Edited by..." I really don't know about other staff. If you want to PM me the link to the post I can see if I see anything.
Unfortunately there is nothing obvious I can see. Maybe someone else will know more.
It is a default vBulletin option to be able to turn off the "Edited By" notice by usergroup so if someone is setup that way I'm sure it's just being used as a VB feature, no one is going into the database to make minor changes.