Game mode: Singleplayer
Problem: Bug
While exploring The Passage, nothing attacks me, except the Skeletal Serpentman on the way out (into the Frozen North). None of the Spiders, nor the Locust Queen, not even after I attacked them. I stood there, and killed the Locust Queen with an Iron Pike, which took about 20 minutes of attacking, and not one thing in there attacked me.
Repro steps:
Same problem here. My Thrall won’t even follow me halfway down the stream toward the waterfall. She just stops. Then when I get inside, nothing moves or attacks.
Upon exiting The Passage into The Frozen North, I heard my thrall die but I can’t find her. Lovely.
Hmm, seems like AI-pathing or something isn’t set up there?! 
Something like that I guess. The critters make noises but they won’t move.
Fighting the boss again, I somehow got inside her hitbox and she started attacking me, but she couldn’t hit me and I couldn’t move. After a bit I managed to roll out from under her. She turned to face me for a few seconds but stopped attacking and still wouldn’t move and the de-aggro’d.