Rapid transit into Nether Portal keeps player coordinates the same

Partner Team Reporting: The World Foundry

Verification builds:++ 1.16.221

Summary: When entering a Nether Portal 'quickly' (try flying into it for reliable repro), the player coordinates at the destination are the SAME as at the source dimension. Works either way.

Impact: Marketplace product with a reliance on Nether travel may appear bugged as the player has no auto-return path and may perish alone.

Repro Steps:
1. Create new world, Creative is fine. Enable coordinates and note the coordinates
2. Create a nether portal in the Overworld where you spawn with Obsidian and Flint and Steel
3. Equip Elytra and glide into the portal from a height

4. Note the coordinates in the Nether - the reproducible case has the same coordinates as the player had in the overworld.

5. Return (walk) through the Portal and note you are at a new location in the Overworld.

Observed Results:

Player is not subject to the 1:8 rule with Nether location when this bug occurs. 

Expected Results:

Nether Portals should honour the 1:8 dimension rule even when entered "quickly".

Screenshots/Videos attached: Yes

Regression Builds:

Notes:

This doesn't REQUIRE Elytra flight, and has been experienced just by walking into a portal. The Elytra seems to be a consistent reproduction though.