Steps to reproduce:
- Create a world with the seed 800095968237666036
- Teleport to X = 27, Y = 34, Z = -1619
- Create a nether portal on the north wall, adjacent to the lava pit
- Go through it
Portals should seek adjacent air blocks just like how portals generate above oceans with a platform.
Both sides of the portal are completely encased by basalt, blackstone, and gravel.