Swimming issue regarding terrain water

Okay, so… I made a custom swimming system in roblox’s terrain water.
Please note, I disabled their water using humanoid:SetStateEnabled, but…

For certain models, this happens.
https://gyazo.com/baf8a256f7bdd95e23da6f40a53a3e87

On the other hand, it works flawlessly for some models.
https://gyazo.com/27bfd3131f6f62e1f5043d085123dd27

Please note, I’m using a Body Position to achieve swimming.