Dupe shulker box

Dupe shulker box use nether.

Sequence of actions:

1)Fill the shulker box

2) Go to nether, and press button "save & exit"

3)At the moment of teleportation through the portal. Place the shulker box at the last moment.

4)Close the game without leaving the portal. 

5) Enter the game and see the result.

It may not work the first time. That's all.