We experienced multiple game crashes (different game builds) and the reason was the skill parasite.
Today for example I tried to capture a Devourer (I know I cant control him). And as soon as he died 2 player get a crash to desktop and me and the 4th player got a disconnect from the game.
This happens so often that I cant run my full necromancer build because it sucks when the game crashes for some or all player if I capture one (or the wrong?) enemy.

Never had problems in SP and it seems that some monsters are safe to control. But since I'm not sure I removed the Parasite skill for now.