Looks like you accidentally modified a admin boundary here; you can filter them out in ID using (map features) in the map data panel to prevent editing them. If you find buildings which are not square check if their geometries are good if so it may be possible to simply square them, however in this case the geometry should have been improved as overlap errors may not be addressed by squaring alone.
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            Published using OSMCha: https://osmcha.org/changesets/164178014
            