Cats are not spawning at night. 

I have an iron farm set up to not kill the cats, and I use it to get tamed cats. I have used it this way many times to get black cats, which will only spawn at night on a full moon. However, after waiting hours going through the moon phases to try to get another black cat, I realized that it isn’t just black cats not spawning, and it isn’t just on the full moon. No cats are spawning any night. I tested this over two moon cycles, so several in-game days, and not a single cat spawn of any color after the sun sets, until the sun rises again. 

Of course, the only thing this really affects is black cat spawns, because they cannot spawn at any other time but night, on a full moon. All other colors of cats can be obtained just fine during the day. 

To recreate, set up an iron farm, and wait until night. No cats will spawn until after the sun rises. 

Please let me collect my black cats again, they are my favorite.