I was alerted today to 3 ad user accounts that had populated over to the GAB. I confirmed in Exchange that those accounts didn't have any active emails attached to them. They were for some reason members of a few distribution groups, but I removed them from those groups, and they were still located in the GAB. I verified there was no freak address put into AD as well. The user that noticed these addresses was not in cached mode, so I am thinking they populated within the last 24 hours. We have had no major changes to our Exchange server, so I believe we are just trying to delete out three non existent emails from the GAB.