M163 and m901 not working properly

The m163 and m901 seem to be broken and they can’t float on water when both of them are amphibious in real life except a variant of the m901 that has a .50 cal but since the one in warthunder doesn’t have the .50 cal, I assumed it to be the variant that is amphibious and in game they both extend a flotation plate when in water but they still sink to the bottom