If a player sets their spawn point while standing on that same spawn bed, they will be placed inside that bed upon their next respawn and the game will try to correct this by forcibly pushing the player out. This can often lead to deaths from fall damage as this bug is likely to push the player off cliffs without any input.

Steps to reproduce:

1. Launch Minecraft Preview (1.21.60.21)
2. Create a new world in creative mode
3. Build a 2x2 platform suspended 24+ blocks in the air
4. Place a bed on that 2x2 platform
5. Stand on the bed and set your spawn point
6. Jump off the 2x2 platform
7. Click the respawn button

Expected Result:

The player is either placed on top of the bed smoothly, or beside the bed on the 2x2 platform.

Observed result:

The player is placed inside of the bed when they respawn and are then pushed out of the bed with no player input, leading to death from fall damage.