The punch list comparison is spot on. “Done” and “accepted” are different events with different owners, and most trackers treat them as one status. Your estimate example also fits the overlap check well. Two trades carrying the same scope is the duplicate case. Neither one carrying it is the gap case, and a snapshot check can’t catch that one, because there’s nothing on the board to compare. That might be worth its own post.

Agreed, the gap case is the hard one. The only way I've seen it caught is comparing against a list of what should exist, not what's on the board. In estimating that list was the scope checklist for each trade. Something has to say a line is missing before anyone can notice it. I'd read that post.