I've seen so many retarded spawns. I remember seeing some deep under water, on the side of mountains, and under houses.
Next time you go into a cave / closed area like the mines, angle your camera behind a wall. You'll see so many lonely poor minions stuck back there. This also causes a lot of combat glitches too. Most likely if you ever get stuck in combat after a fight with minions in one of these environments, this is likely the cause. XD