Mobs spawning TOO much in custom biomes

I have custom biomes in my mod, and it's a hell because mobs that aren't supposed to spawn spawn insanely (pigs) to the point it impacts performance.

it's even worse when you put a mob in entity spawning because even with a weight of 2 it will spawn in gargantuan amounts.
The worse thing is when you allow them to spawn in groups larger than 1.
If you could fix this by just adding a mob cap, it would be cool.
Also, I put 8 weight on a mob and it won't ever spawn, but i put 2 on foxes and they keep on spawning by hundreds.