I had this happen several times on Tuesday and Weds. For me, I would be booted from the game while performing some kind of action. It seemed to be related to typing in chat while performing some kind of action. The client shutdown and when I tried to log back in, I got the "You are currently logged in" message. This seemed to last until the server was reset.

That being said, today I was able to play for about 5 hours without any huge problems. I had 2 client crashes during that time, but I didn't have any problems logging back in.