How a self-inflicted cache poisoning made a live article return 404 for 23.8 hours

A development team discovered that one of their published articles was returning a 404 error exclusively to their own systems for nearly 24 hours, while all other users could access it normally. The root cause was a cache poisoning incident they had triggered themselves: their stats-collection job had requested the article's public URL before it was published, causing a CDN edge node to cache the 404 response. When the article went live, the origin server served it correctly to the world, but the team's runner kept receiving the stale cached 404 response — complete with headers showing a cache age of 85,673 seconds. A cache-busting query string failed to help because the edge node's cache key did not include query parameters, making it impossible for the team to bypass the stored response from their own network. A secondary bug in their error-reporting logic compounded the issue by making the single affected article appear as a 44-article blackout in their monitoring dashboard.