Mobs going over the mob limit and causing excessive mob spawning

Mobs spawning in excessive quantities and ignoring the game's creature limit, spawning is also abnormal in which mobs only spawn in groups of 4-8, and both hostile and aquatic mobs try to fill their caps instantly, treating it as a minimum rather than a maximum.

Test Video:
https://youtu.be/Pba-vZNLpe4
Seed: -6973248283818474784
Coords 1: -1626.433 / 66.00000 / 732.763
Coords 2: -3410.374 / 69.00000 / -2492.913