ArtemisLib's eye height logic is located at com.artemis.artemislib.util.AttachAttributes#onPlayerTick

I made a patch mod to fix this and many other incompatibilities. It seems the eye height factor should multiple like this to get the correct eye height

I'd prefer to have the compatibility fix within Aqua Acrobatics to avoid breakage and so an external mod is not needed, if you give permission. Your fix seems to make sense although I don't understand where the multiplication by 3 comes from?

Yes, double mixin is always not a good idea. As for the factor 3, see here. My mod patched ArtemisLib to make it use CPM size but somehow made it multiple 1/3 twice here, so I have to revert it.

@kappa-maintainer Does e3bfb9f work for your mod? I haven't released it yet in case it needs further tweaking.

I will test this

It works perfectly under many mod combinations, I should remove my double mixin now
How the 1/3 got multiplied twice is still a mystery though

Great! Released as 1.14.1.