mobs are not spawning in my custom dimension after update

the mobs i made after the update of 2021.2 doesnt work, they dont spawn naturally, they work as a mob, like i can spawn them in using the eggs, but they dont spawn normally, i set the mob type to mob, didnt work, creature, didnt work, ambient, didnt work, i changed the spawn rate higher, didnt work, lower, didnt work, and i tried restarting my computer, didnt work, changed it to an animal type, didnt work, changed its group size, didnt work. its not the biomes messing up because i already tested it with the previous mobs i made, but these new ones just dont work for no apparent reason. help me out here