You can check out it here:
https://imgur.com/a/A2bGu4A

I dont know if this issue because of this mod or flans. Modular Warfare that adds guns too doesnt make any conflicts.

Unfortunately it looks like Flans reimplements a lot of the vanilla rendering logic here, which will cause issues since Aqua Acrobatics only patches the vanilla renderer. I don't think I can fix this easily on my end, sorry.