Now I have seen this kind of thing before when I kept guppies. Had it where they had ich spread thru the tank like wildfire and once I got them all cured they had hole like spots on em from where the ich was attached. Literally made it look like the fish had bites taken out of em. Who knows maybe something similar happened to these angels and they were just recently cured of ich before shipment. Granted without knowing how they were kept we'll probably never know the true cause of it.