Armored Bearger still makes his hurt sound when disabled, where the other two mutant bosses don't

When armored bearger gets disabled by being hit after doing a slam with his bottom, he will still make his hurt sounds as if you were hitting him normally. 

However this is inconsistent with the other two lunar mutants who make no sound when they are in their disabled state (which makes more sense thematically since you are basically hitting a lifeless corpse).