Trial chambers generate an air pocket within the pool of water at the end of the corridor.
To reproduce, use the seed -1916179195248682850 and run the following command:
/execute in minecraft:overworld run tp @p -272 -33 -413 180 90/execute in minecraft:overworld run tp @p -272 -33 -413 180 90Attachments
Comments 2
The provided seed and coordinates no longer work as of 24w34a (although they do lead to an excellent example of [MC-266435]). I found a different trial chamber with no air pocket in its water pool, so the issue may have been fixed.
For the "fixed" trial chamber:
Seed: -7791476409053505400
Coordinates: /execute in minecraft:overworld run teleport @s -2920 -23 31343 -225 36Seed: -7791476409053505400
Coordinates: /execute in minecraft:overworld run teleport @s -2920 -23 31343 -225 36
Can confirm in 1.20.5. Seed 3057310577815726585 at coordinates 14 -34 302.