The bug

Strongholds can no longer be exposed due to the new change in 21w07a that lets strongholds be surrounded by stone instead of being floating in the air. This also affects oceans too and seems unnatural.

How to reproduce

1. Use seed 1093906406674575866 in 21w07a
2. Teleport to -1051 44 1165
3. Dig down to the library under the floor
   → The stronghold generation in oceans no longer get exposed and seems unnatural