Is the AI lowkey clever?

I recently went into a burial crypt, and there was one single undead sitting at the entrance. He didn't notice me at first, but eventually he caught aggro and did the usual dance around the entrance platform. Eventually, though, he began to oddly start swinging at one of the doors in the main "lobby". And the funny part is, there were 3 doors to choose from, two with skeletons trying to come through, but this one specifically had a bowman I came to find out. Just kind of odd, and clever in a way.

I've also had situations where greydwarves decided to join in on a fight between a troll and I, except they would only stick close to the troll and seemed to kite my attacks and only throw stones until the troll would swing at me. This was also very odd.

So I'm wondering, is this just some random glitch or maybe some other explanation as to why the skeleton did what it did? Any does anyone else have any funny/eerie/crazy stories to share about the game's AI?

I guess it's worth mentioning that my game is, I would say, heavily modded. Mainly with QoL features, but there's definitely non-vanilla things in there such as Creature Level/Star/Power modifier, as well as added enchanting/runes, but nothing outright crazy that modifies the AI's very behavior (that I know of!)