Anvil does not drop item ordissapear when it falls as very damaged anvil (and should break)

If you drop a very damaged anvil enough blocks to break it, and it lands on a half slab, the entity will stay there. It still works as a regular anvil, damaging mobs whin it falls, but it does not become a block again. So far dropping it into the void from breaking the blocks underneath works, and i think that relogging also works.