When you respawn or enter a new world, your world spawn is not exactly in the middle of the block you spawn on, but is off center and is always in the corner of the block. This can break some maps where you respawn in a box that gives you all your things back or does something else, and you spawn outside of the box.

Steps to reproduce:

• Set the respawn radius to 0.
• place a block on the world spawn that is not a block around it.
• use /kill in survival to die and respawn.
• notice that you don't spawn on the center of the block, but in the corner, no matter the block that is there.

What should happen:
You respawn in the center of the block.