Only one layer of blocks in this screenshot is basalt. I expected it to be 2 or more. One of them extends 2 blocks but that's it. Seed: 3264540676790285439
Relates to MC-199004, MC-199005 and MC-199006.
New nether forest biomes replace the top layer of blocks with the respective nylium block, even if the blocks being overwritten aren't netherrack; leading to unnatural looking terrain
Soul Sand Valleys replace the top blocks with soul sand/soil despite the blocks being overwritten being something else
Gravel patches only generate on the top layer sometimes