See attached screenshots. Trees, ores, sand patches, flowers, tall grass, lava and waterfalls, etc are different.
For reference, the screenshot without lavafalls is 18w06a and the other one is 1.12.2.
MC-124985
Terrain population is different from old generation
Resolved
Works As Intended
2
The worldgen refactor changed the way decorations are seeded, so changes are expected. Heightmap should be unaffected though.