Can be tested by generating a world with any seed up to snapshot version 20w21a and then generate a world with the same seed in version 20w22a. All dungeons generate in different locations
Top part of the image shows a cobblestone-spawner bug. In bottom image, same location but neither dungeon generated, same as all the other dungeons
*Posting because seems like a big change that wasn't mentioned in the snapshot's article so might be unwanted
Thank you for your report!
However, this issue is a Duplicate of MC-186093.
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