I set up uptime monitoring for my sites and nearly made every check meaningless. They all sit behind Cloudflare, and a plain HTTP check there proves that Cloudflare answered, not that my app is alive.
I re-downloaded a spreadsheet export and got the version from before my last edit. Another machine got the current one. Nothing in my app was wrong, and nothing in Excel either.
Every deploy was green, every page worked, and one file returned 404 in production. The cause was a Hugo module mount behaviour that is documented but easy to miss.
