Shulker Boxes do not keep their contents when broken

Put the summary of the bug you're having here

What I expected to happen was...:
The shulker box would drop and contain everything I put in it

What actually happened was...:
The shulker box broke and dropped as a regular chest would

Steps to Reproduce:
1. Place down and open the shulker box
2. Place any item in the shulker box
3. Break the shulker box