If the new 1.20 structure, Trail Ruins is spawned in the world with /place structure Trail_ruins it breaks any bedrock below it leaving the void available
MC-261289
Trail Ruins Can Break Bedrock in Superflat worlds if spawned with /place
Resolved
Invalid
0
/place is not limited to generation rules, and forces placement, even if it normally cannot generate at said location (such as too low in the world).
The fact the structure replaces all blocks in the area it generates is by design, bedrock is no exception for ANY structure. If you can actually reproduce this issue without the use of /place, then it is a valid report.
The report, as it is now, is similar to saying "I can use /fill to remove bedrock".