Minecraft wiki entry for Development_versions, associated text: MC-236947 – Signature attribute is stripped from java records.
MC-238930 – Soul Sand and Soul Soil generate below the nether ceiling.
MC-238959 – Falling block placing at Y=1 changes into dropped item when landing on Y=0.
MC-239880 – Some chunks have missing blocks below 0.
MC-239900 – Upgrading custom world to 21w43a ignores min_y and height.
MC-240513 – Pandas do not spawn in bamboo jungles with Default world.
MC-241263 – Off-heap memory leak.
MC-241409 – Game crashes when terrain shaper data is missing.
MC-241630 – Temperatures don't properly get converted.
MC-241636 – Snow golems don't take damage in hot biomes when a cave biome is underneath.
MC-241767 – Breaking a vine or ladder block while the player is climbing it while sneaking allows the player to hover in place indefinetly.
MC-241820 – Ocean Monuments upgraded from previous versions appears to have the bounding box shifted to chunk borders north and west.
MC-241830 – Windswept savannas in amplified worlds have the incorrect surface blocks.
MC-241941 – Nether bedrock roof can generate exposed.