Rooted Dirt does not Replace Sandstone During World Generation

Expected behavior: Azalea Trees generated over any terrain have a system of rooted dirt which continues down to a lush cave.

Observed behavior: The root system of Azalea Trees that generate over sandy environments (specifically observed on a snowy beach, but might generalize to beaches, deserts, and badlands) replace sand but not sandstone during world generation.

Observed in seed: -3614959699821190895 at X:-731, Y:-1028.