I lost months of Google indexing to a single missing UA pattern

tl;dr — If your site has any kind of geo-gate, age verification, or country-specific wall, and you wrote a "let Googlebot through" rule in your middleware: your rule is probably wrong. Google's URL Inspector does not send a Googlebot UA. It sends Google-InspectionTool. Match that explicitly, or you'll lose months of crawl budget without ever seeing the cause in Search Console.

I'm shipping noctias.tv — a multi-language portal — alongside our older domain noctias.com. While verifying the new domain in Search Console, every single URL inspection failed with the same message:

"ページをインデックスに登録できません: noindex タグによって除外されました"

("Cannot be indexed: excluded by noindex tag")

But the page wasn't noindex. Curl with a Googlebot UA returned <meta name="robots" content="index, follow"/>. The page rendered correctly to humans. The sitemap was healthy and showed 252 URLs discovered. Bing indexed it. Search Console said: nope.