Description from EVGENSYPERPRO

The nether can generate stone next to gravel. This may be rare.

Seed: 1172033112
Coords: 99 32 275
Coords: 178 33 113
Coords: 281 33 60
Coords: 297 33 133
Coords: -12 33 -502

Steps to reproduce:

1. Create a world with the above seed.
2. Go to Nether.
3. Set the above coordinates in the Nether.

Observed results:
A stone has been generated in the nether.

Expected results:
No stone should be generated in the nether.

Original Description
I found some stone and copper that naturally generated in the nether while playing beta 1.17.40.23 with experimental mode enabled.  Seed 1172033112.  Coordinates in picture attached.

Haven't found it yet on the new 1.18 beta, but I couldn't figure out how to put the old one in the version.