im playing a super rampant deathworld with bobs right now. i noticed most biters after getting hit from a long distance by something like a plasma turret, give up and stand still while the remaining 25% that split out of the attack continue on and die. i think its really silly that 75% of the biters just charge in, get scared, and wander off to nuke my ups. i think the problem is biters after being split are left to find a target and attack it, when what they should to is copy the a.i state of the parent biter.

sorry for typo in title lol only now noticed it and it wont let me edit it

This can only by fixed by Wube. If you enable debug overlay and enable "group" and "order" overlays, you will see that spawned biters do have order to move/attack, but they don't do this. BUT, also, sometimes, their group gets disbanded, but in this case they should just roam around, and not stay still. I tried to fix this multiple ways, but nothing seems to work.

What i noticed though, is that this happens only if you have considerable amount of biters on map already attacking your fortifications.

alright well in that case im leaving this note here for people having this issue in the future: increase the evolution factor manually, stronger biters require more pollution to send attacks with, /c game.forces["enemy"].evolution_factor=X should be the command to manually change evolution factor for ups saving (credit goes to the wiki).