Thats strange, but i dont believe it... A zombie hitting you wouldnt make you lose hp, when zombies hit each other no damage is done, when zombies attack the game wouldnt make their attack reduce damage, the game knows that when a bullet hits you it does (x) amount of damage, but when a zombie hits you it has no (x) but a (Y) so that a different change accours when a zombie attacks therefore i say bullshit