Affects Version/s: TU37/CU28/1.29/Patch 8
Fix Version/s: TU39/CU30/1.31/Patch 10
Affected Platforms:PlayStation 4
What I did: created a few superflats with biomes specific to rabbit spawning and made the top layer iron blocks.
What I expected: no passive mob spawns
What hapoened: rabbits were able to spawn in each test.
Conclusion: There seems to be an error in the spawning code where the game checks the block selected by the spawning algorithm that causes the spawn to fail if it is not grass or one of the sand variants (perhaps sandstone and hardened clay are intended as well, I'm not sure). Please check the code and fix as this issue causes problems with mob cap.