Summary:
The player spawns off-center on the obsidian platform in End. That is, the player will spawn at coordinates 100 50 0, instead of 100.5 50 0.5. When players spawn in the world or respawn, they spawn in the center of the block, and this is also a parity issue - this was fixed in Java 1.16.2.

Steps to reproduce:

1. Teleport using the end portal to the End.
2. Look how you spawned on the obsidian platform.

Observed results:
You will spawn off the center of the platform at coordinates 100 50 0.

Expected results:
You will spawn in the center of the platform at coordinates 100.5 50 0.5.

Screenshots: