Cursed Earth only spawns Grottols

[SmokeWeebEveryday]

Exactly what the title says. I created a mob farm (using cursed earth, mob mashers, and mob fans) but the only mob that spawns is Grottols, and only one at a time. I attempted to disable Grottols in the config, and that simply resulted in no mobs spawning on the cursed earth. The mob farm is far from the world spawn. There aren't any peace candles nearby.

[SmokeWeebEveryday]

Looks like the cursed earth area was clipping into a mushroom biome. Mobs can't spawn in there.