Observing?

[Zonk]

Observerd a Player and always got a Gamecrash after like 30 second.
Got told its because of different Act but then i joined a rush game and they all observerd act 5 Baal from act 1.
I tryed again and after hitting observe i see player walk 1-2 seconds and then screen freezes again until he use a tp. someone have a idea about that?

[Damakos]

If you are spectating someone and press the p button (party), you will instantly crash. Is that what you are doing?