@Herotu, I don't think a particular costume part is the problem. I just created a new character with a reset costume (plain black tights all over), changed it's second costume slot to have flared gloves, and then repeated the process. Crashed the client
Edit: And after a further test, it seems you don't even need to be unconscious. If there is a costume change queued up, as it were, and you zone before your constume changes, the client crashes.