Yes, at least on USEast. First, I was doing a Baal run yesterday, and after killing all the monsters in his throne room, he just sat there casting decrepify and didnt start summoning any minions. I figured we missed a monster, so we went and killed every monster in the level, and he still didnt summon his minions...we ended up having to start a new game.

And then today, I was going to do Andy with my necro, and the zombies in the catacombs were somehow bugged as that they couldnt get hit by physical damage. I had 3 skellies pounding away at a single amp'ed regular zombie, and it was as if his defense was 10000...they could not hit him. I was able to kill them with my act 1 merc which had a bow with lightning damage on it though...I noticed when the merc fired Fire Arrows they did no damage either.