Stackable items duplicate when block under them is moved in creative

Go into creative mode
Put a piston next to a block
Put a stackable item in your survival inventory
Drop it from your inventory onto the block with Q
Activate the piston
The dropped item should come back into your inventory as 2 and the stack will double every time

Only works in creative

https://www.youtube.com/watch?v=A8HQuSKm44Q