Steps to reproduce

1. Create a world.
2. Go to the end.
3. Spawn 200 mobs, like sheep, or fish in an aquarium.
4. Go back to the overworld.
5. Explore various undeveloped areas.

Expected result

Mobs spawn.

Observed

Mobs do not spawn.

After we updated to 1.19.71 all Endermen disappeared on the main End island I'm terraforming. Ive gone in caves with zero light no mobs, the nether has no mobs, not even fish are spawning. I double checked that Mob spawning is on and the difficulty is set to hard. The only mobs that are spawning are from spawners. All villagers and animals we had before the update are still here.