Hostile mobs are not spawning in my over world naturally. Difficulty locked on Normal.

I optimized my world from 1.13.2 to the snapshots and have not had natural hostile mob spawns, I get skeletons from my mob spawner and I've gotten pillagers but no zombies, spiders, endermen, creepers, or skeletons. I get blazes and pigmen as well as ghasts in the nether but my overworld mob spawns are non-existent.