Shulker anvil

When an anvil is dropped onto a shulker it will stay on/ rotate with the shulker for a while, the randomly disappear and show up as an item drop.\

What I expected to happen was...:
The anvil would
a) kill the shulker
b) just stay on/ rotate
c) break

What actually happened was...:
A combination of b and c above

Steps to Reproduce:
1. Build a few blocks into a tower
2. Place anvil on top
3. Spawn Shulker underneath
4. Mine blocks so that the anvil falls onto the Shulker