Blocks doesnt keep the "CanPlaceOn" Tag after being Placed

Blocks doesnt keep the "CanPlaceOn" Tag after being Placed but they keep names and such...

The Shulker Box could be really usefull as a backpack in adventure maps.

but you can place them only once...

I know its maybe abit like a suggestion... but if the shulker box keeps the name... maybe its a glitch if it doesnt keep the tag! I dont know! but to be honest it doesnt really metters because its a thing that should be changed/fixed