Can house mutations overwrite good mutations?

Can an overnight mutation from the mutation house stat overwrite another cat mutation or only birth defects?

I know for sure even mutations can do that, and I know house mutations can overwrite birth defects; but I am not super sure if they can also overwrite good mutations. I never noticed it happening, is it possible it goes for non-mutated / birth defected parts first or did I just not pay attention to the mutations?