Shulker boxs that have can_place_on tags, will not be placeable once items are in the box.

Steps to reproduce:
/replaceitem or /give yourself shulker box with can place on grass stone anything.
Take shulker box in adventure mode(its the only mode u need can place on) and confirm it can place where tagged.
Put items in the box
First thing you notice is there is no longer the canplaceon tags, its the items in the chest.
Try to place the box on blocks that it was created to allow, and it wont place. No longer has proper components to place!! Not cool for custom adventure map makers. PLEASE MOJANG!! Lets get this one rushed.