Fun random bug i encountered today

[Bendiix]

I joined my friends game and this happend.

Diablo 3 Deckard Cain Dance - YouTube

[who knows]

I produced this bug the day the patch came out. Steps to repo:

1.Do the quests, "Talk to the ferryman" -> go through all the steps until you go back to New tristam and go into cain's house and see the cutscence.
2.Exit cutscence. Be back in New Tristram, he should be gone but he isn't. Upon talking to him he disappears.