Um hello?... so I’m in 1.14.3 and I can’t get any mobs to spawn in the overworld. Mobs that spawn in a special way like phantoms and mobs that come out of mob spawner will spawn normally with no issue. I’ve been playing in a new world created in I think 1.14.2? Maybe I don’t remember, but I didn’t have the issue until I updated to 1.14.3
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Duplicates MC-155289. If you are having these issues in 1.14.4, post a debug report to that ticket as described in the mod notice.