The absolute most useful thing you could gather, if you get to a place where you can reproduce it, would be a HAR file: HAR Analyzer
It contains unique identifiers per-request that will help us understand when a request was served, and from which deploy. More details about these are described in this article , but a HAR file is preferable since it will get that detail for EVERY asset, and getting the x-nf-request-id for a 404 isn’t as helpful as getting the one for the asset that referred to the 404’ing path (since that will show us “served long ago” → we’d expect the behavior your see, or “served fresh” → bug here).
Thanks for your help in troubleshooting!