Pachy survives height after dropping it. Happens more often but not always

Sometimes when i clamp a Pachy with my hatz and drop it. it will fall very slowly and survive the fall without any damage. this happens rarely but it happens. it happened like 10 times in a couple of months. only happens with pachies

i saw the pachy fall very slow after i dropped it

it supposed to die after the fall or if its not high enough deal damage and bone break