User blog comment:DaNASCAT/Technical Update: September 20, 2011/@comment-5753466-20110923174118/@comment-3187795-20110925215054

That's happened before with me, as i was logged out on the wiki, but still shown as logged in on chat. Simultaneously on and offline isn't liked very much by chat I guess. I closed the window, re logged in, opened it back up, and it was fine. Your problem may be different though.