The alien AI was a mess. It tried too hard to be clever. The code was fragile and the behaviour unstable.

I threw it all out and implemented a simple flock / boid algorithm. The aliens will stick together and try to approach the player in natural looking groups.

A* pathfinding is gone too. Instead, the player character drops invisible scent markers with a limited lifetime. If aliens cannot get a clear line-of-sight to the player, they will look for the scent dots and follow them. That can eventually lead them back to the player, even around corners etc. It makes it look like the aliens know what they’re doing. Which, of course, they don’t.