So, I've created a superflat world under the "Overworld" preset... And I've found that every single structure that can spawn, does! Jungle temples, witch huts, igloos, even the new underwater structures above water! I am sure this is a bug and will be addressed/fixed in the coming weeks. Wanted to bring it to attention.
Thank you for your report!
However, this issue is a Duplicate of MC-124918.
If you have additional information, please add it to that report.
Please search before reporting, as it's likely that one exists already.
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