Just updated and now every mob farm on the map is broken, literally wont spawn anything.
Conditions, sky spawners definitely not having the cap taken up tested multiple times with one person in world.
Seem to still spawn on ground level.
Recreate go up to axis y 200 and build a mob farm. The result will be no spawns.
Stood at this normally very active creeper farm for 2 m/c days and nothing has spawned.