Summarization of attached video:
1. Enter existing Nether portal at -40, 84, 328
2. Arrive overworld at -324, 30, 2626
3. Return to Nether and arrive at -41, 34, 313 and there is no portal there.

nether portals with synchronization error.
When entering or leaving the nether, the portals are teleporting us in random places away from the portals.
I look forward to corrections! 🤗