X-ray vision exploit using slab pushed by piston

A player can achieve x-ray vision upward by pushing a top slab into their head with a piston.

Steps to reproduce:

1. Import the attached world "Slab Upward X-Ray Exploit.mcworld" and open it.
2. Under the pillar of emerald blocks, find the gold block in the floor and stand on it.
3. Push the button nearby. Pistons will block you in and push a slab into your head and a solid block into your feet.
4. Look up.

Expected result:
Because of how you're blocked in, there's no place you can be nudged out of the way, forced into a crouch, or forced into a crawl, so you should become embedded in the slab and block.

Observed result:
You are indeed embedded, but instead of a solid block above you, what you see looking up is similar to what you would see in Spectator mode.