User blog comment:Ohmyn0/Chat is Now in Wikia Labs/@comment-1066636-20110706174512/@comment-10370-20110706214402

Yeah, there are lots of tiny interruptions that disconnect and then reconnect you automatically. This was causing a lot of unnecessary "noise" in the chat -- seeing messages that show "x has left / x has joined" when X is doing just fine. (My guess is that the same kinds of tiny interruptions happen in phone calls all the time, but the phone company doesn't break in and tell you about it every two minutes.) We "fixed" that by adding a little delay so that it doesn't send the "x has left" message until you've actually been gone long enough that you're not automatically reconnected. We released that delay and then saw people saying, "Chat is so much more stable now!" :)

It's possible that we may need to tweak that again and make the delay a little longer... We don't want to hide it when someone is actually disconnected, but we also don't want to spam the room with unnecessary left/joined messages. Thanks for reporting the difference in browsers -- maybe we can figure out how to tweak this to take a browser difference into account.