Podzol generates below other blocks

Podzol generates below other blocks. This issue reappeared after it was fixed at 19w14a.

Clones MC-137595

Steps to reproduce:

1. Download the Cold Biomes worldgen
2. Create a new world
3. Generate it through seed 1623146384
4. Teleport to coordinates 189 72 2
5. → Podzol has generated below the grass.

Note: This also can be reproduced without using the Customized world.