Fall into void if set to respawn on pressure plate (logout or via command)

When I set my spawnpoint on a pressure plate using a command block for my minigame, respawning on the pressure plate respawn me into the void instead, at same coordinates, I am using a flatworld for it, because of this bug, I had to replace all pressure plates with strings.

Steps to Reproduce:

1. Create a flat world.
2. Place a pressure plate.
3. Stand on the pressure plate and run the following command: /spawnpoint
4. Die and respawn.
5. or simply log out and back in

Observed Results:
The player respawns underneath bedrock and falls into the void.
Happens on multiple platforms

Expected Results:
The player should respawn on the pressure plate.