Caves generate far less below y=0

EXPECTED: Large caves generate in abundance below y-0

ACTUAL: Caves are much rarer than in previous snapshots.

HOW TO REPRODUCE: Generate any new world in 21w14a and travel below y=0. Caves will appear much less when compared to 21w13a.

See attached image taken at y=-45. There are very few caves; not nearly as many as in previous versions.