Not sure if it's a bug - but behavior is strange at least. The issue is - that if stay in chat room for long time (~24 hours or more), then usual functions to edit my own messages which I've just said, is unavailable. I.e. if I press on message menu - there will be only "permalink" available, or else - if just press the ⇧ (up) arrow on keyboard, nothing happens (instead of displaying form with editing for that message).
If I'll rejoin the room, problem disappears (so I'm unable to edit message that I've just said > I rejoin > I'm able to edit that message) until I'll hang there for long time again. That's why I think it's a bug and not how it's intended to work. Also I'm able to use room owner's functions no matter how long I'm "hanging" - thus, it's not like "I'm logged off".
My browser is Firefox under Linux (if that matters)