It seems that in several quests, wolf AI is broken. I don't know if it's specific quests or if it's just anything with wolf AI, but as I'm seeing it more and more, I'm beginning to suspect the latter.

Wolves will come out of stealth (if they were ever in it) and run up to attack. They seem to get in anywhere from 0 to a few attacks, then sort of shut down, simply standing there. After they're killed, they sometimes don't even disappear, staying there, but they can't be hit and no longer block movement, as if they aren't there.

So far I've confirmed this behavior with:
the dogs of Lords of Dust
the restless wolves of A Small Problem
the illusionary wolves of Partycrashers

If anyone finds more, you're welcome to update this list below.