I’m currently approaching the end of summer, about 4 months into the game, and I’ve been noticing scarred zombies have started showing up with extreme frequency.
I had a horde of probably a dozen show up at my camp. Visiting a small town I’d almost cleared out, I kept seeing scarred zombies wandering around everywhere.
I know there is a small amount of environmental or conditional triggers for certain zombie spawns and evolution paths… so what, if any, causes scarred zombies to appear, and is this intended?
If you are using Wandering Hordes, chances are those were pulled from nearby Beehives.
I am unsure where else they could spawn normally 
but there is also the possibility of them just being able to spawn with a very low % anywhere.
Scarred zombies are found in beehive. Somehow they tend to be very wanderous, compared to other types. On my map they wandered 20 tiles away from the hive and went in huge group.
One thing I’ve noticed is that beehives and wasp nests can spawn on roofs as well, and then those zombies can tumble down and wander about - Giving the impression that the population of a much farther hive has made its way over to you.
There’s also just more wasp nests in 0.G, I believe. I think the wasp radio towers are new to that branch.