Stored items in Shulker Box disappear when reloading a saved game.

Items placed into a Shulker Box disappear after I save and quit a game then reload the saved game.

What I expected to happen was...:

Items stored in the Shulker Box when leaving the game should still be in the Shulker Box when reloading the game.

What actually happened was...:

Items stored in the Shulker Box when leaving the game vanish from the Shulker Box when reloading the game.

Steps to Reproduce:

1. Start a new world in single play Survival.

2. Open the game to multi player with the "Open to Lan".

3. Select "Allow Cheats" in the Open to Lan option menu.

4. Select "Start Lan World"

5. Give yourself a Shulker Box with the "/give" command.

6. Place down the Shulker Box.

7. Place an item into the Shulker Box.

8. Save and quit the world.

9. Reload the world you just left.

10. Look in the Shulker Box, Items you left in the Shulker Box are gone.