Put the summary of the bug you're having here

What I expected to happen was...:
shulkers closed should be like solid blocks

What actually happened was...:
they were solid, and floating 1 pixel above the ground

Steps to Reproduce:
1. put down a block, in mid air can be useful for seeing it better
2. spawn a shulker on top of it
3. see that there is 1 air layer between the shulker and the block