minecraft Skull owner bugs

in the snapshot, the skulls are very bugged. when i try to put a skull with a CustomOwner in the ground, the game crash sometimes. when i use it in my head, shows only the steve skin, not the custom owner. if i crouch using a skull, the skull appears to be floating, it don't crouch with me. if i copy the skull with for my inventory (+NBT), the nbt don't work on skulls with custom owners

sorry for bad english