Yeah, the combat AI itself is a problem. The AI does all kind of weird things and things in incorrect sequence.
DOS2 had a combat AI update at some point to a Larian-proclaimed deadlier AI, which I expect to happen with BG3 at some point. The AI right now is very easy to manipulate and does not account for a number of things.
The AI seems to now very often get stuck and unable to do anything. If their path is blocked they can't do anything. The downside of complex vertical maps where you can block paths with indestructible Flaming Spheres and destroy ladders to be unreachable.
Likewise Stealth is completely broken because the AI doesn't move towards your last known location and start rolling Perception checks. You shouldn't be able to hide in plain sight after attacking anyway and the vision cones are way too short and narrow. And only Rogues should be able to attack > move behind terrain > hide on the same turn. Hide as a bonus action for everyone really robs Rogues, can't understand why they change the rules like that. 5e already has an answer: multiclass into Rogue on your Fighter if you want to get that Bonus sneaking.