1. Version 0.14.19

2. Initial attack when pollution hits them, no further attacks...

3. Spawner is absorbing pollution continuously, ensuring that it is being nearly surrounded.

I'd upload my much bigger factory that is more than engulfing spawners but it has mods, so I just started my 4th game ...

Starting conditions are all default except starting area is small or extra small. Confirmed peaceful mode is off.

I've tested this four times and it "replicates" every new game. I've disabled all of my mods as well to confirm. The biters are sending an initial attack (usually just one) when pollution first gets to them, after that, the nest does nothing. I'm attaching my save game to show you, I'm putting a ...