EDIT

I didn't test this correctly. Please mark this as Invalid.

The Bug

All entities face west when entering an End portal, not just players. This is unlike 1.20.6, where only the player faces west when spawned on the obsidian platform, while other mobs retain their rotation.

This change was never mentioned in the changelogs, but it is most likely caused by the fix for MC-272879.

How to Reproduce

1. Create an End portal using End Portal Frames and activate it using Eyes of Ender.
2. Fly above the End portal and run the command to summon a creeper: /summon minecraft:creeper
3. Run /tick freeze to note how the creeper faces west.
4. Go through the portal. Note how the creeper faces west instead of south.
5. In 1.20.6, mobs retain their rotation when entering the End, which seems to be the intended behavior.