Yeah StreetComplete is purposedly simplified, so it doesn't handle gracefully all cases, like dependencies.

For example StreetComplete also asks for addresses on buildings even if they are already mapped, so some quests shouldn't be answered right away.

>Undo all my problematics issue

If those two building parts have different attributes (meaning tags), they should stay split then. So there is no edits to revert, just this note to close.