When a player teleports through a portal from the Overworld to the Nether, chunks generate far away from the portal

Steps to reproduce:

1. Create a new world with seed -1408554467
2. Check generated chunks in the saves folder
3. Run tp @s 3500 ~ -1600 and build a nether portal nearby
4. Go through the portal and go back
5. Check game files again
6. You can find in the DIM-1 folder that chunks were generated far away from the position of the portal

Expected Behavior:

No chunks should be generated in those regions