I will be in a cinematic screen with Tsu-wee (the Last Legion quest giver near The Jade Citadel x:814 y:262) when he will suddenly boot me from the conversation and become invisible. The "!" or "?" will stay floating above his head, though he will not be there. I have logged out, gone into another zone, waited for day/night to change, and he seems to return in about ten minutes, but bugs again after picking up/turning in one quest.