Logged in as another user? Edit posts, approving new members, banned

[kh99]

Yes, it sounds like there's caching going on somewhere. If you have any kind of caching control in an htaccess file, make sure you're not including php files. Edit: well, now that I think about it that might cause login/logout problems, but wouldn't make it look like a user was logged in as someone else, so it has to be a problem somewhere else.