Findings
Each of these was found on live work and raised no error anywhere. They are written up for what kept each fault hidden, since the fix is usually the short part.
September 2026 · verification
A build loop overwrote six finished products with a seventh. The automated verifier passed all six, and it was right to. It checked page format, buyer data, watermark invariants and the text layer. It never checked that the document was the product named on its own cover.
Summary · my own code
A marketplace's structured "sold modification" emails are first-time purchases with the modification baked in. My parser read the base price and then dropped it from every total, for fifty orders across six years, with a comment in my own source asserting the opposite. The version-over-version diff is what caught it.
Summary · my own configuration
A crawl block and a noindex tag on the same forty-five pages. A noindex only works on a page the crawler is allowed to fetch, so blocking the crawl guaranteed the tag was never read and the URLs were indexed anyway, title-less.