Bedrock spawning in trial dungeons when a room is near the bedrock level
How to recreate:
Open a new world in 23w45a
Search for a trial dungeon in spectator at about -58
Search until you find one that looks like the image i provided as a attachment.

Or
Make a world with the seed -2683458371323364231 in 23w45a
And go 1902 -58 817
Command to teleport to location. /execute in minecraft:overworld run tp @s 1902.88 -58.87 817.33 2969.02 34.60

I have not found any that go thru bedrock but there may be some.
In conclusion the structure spawns in bedrock sometimes.