Factorio Forums

Steps to reproduce:
Open the save below with the mod.
Throw a large amount of biters near the player.
Walk close to the turrets to the east(the armor will protect you).
Biters randomly start to disappear.

Are you sure they're not just dieing?

The Biter AI is programmed to kill off biters if they've got nowhere to go, have no "spawn point" (base spawner) and they can't reach what ever they're trying to attack after a given number of times.

It's a method to prevent stuck biters from eating up CPU time when they can't go anywhere or do anything.

Sounds like the third reason, except they don't die, they literally just vanish. But yeah, I guess it's intended then.

Although I would prefer if my biters didn't just disappear like that, I guess it's avoidable by just staying away from the turrets.