Im not sure if its a feature or a bug or something else but Ive noticed that a lot of monsters are no longer hostile, even though it says they are. manhacks for example. I can walk through a cloud of the things and even though they are all hostile, they will not attack. the same goes for skeletal and bloated zombies. even more alarmingly, I encountered a shoggoth which had no interest in myself or the NPC following me. It didn’t even follow me out of the room or bang on the doors after I left. most monsters still have normal aggression, but otherwise hostile beings are simply ignoring me.
It is of note that this is exp 3250, so maybe its been fixed by now if it was a bug.