Hard edges when new caves generate near surface.
Coordinates: /execute in minecraft:overworld run tp @s 2612.51 74.30 -409.27 -21.19 29.55
World Generation on 21w06a
Flat and Unusual Terrain Generation Next to Caves
Water caves cause land to be excessively flooded
Unnatural shape looking like a chunk border but appears to be completely unrelated to chunk borders