Pressing Q + right-clicking a block while holding a double block only shows the top of the block. Bed disappears and the double chest becomes a normal chest with a buggy part.
- Have a double block in the inventory bar
- Look at block
- Do Q (throw an item) + right click (place a block) while having a double block in hand
- The item thrown will go into the lower half of the block and there is only the upper half of the block