From Netlify: Hey everyone, this was definitely an issue on our side. We were testing an internal change to our routing mechanism and returned a testing message

From Netlify: Hey everyone, this was definitely an issue on our side. We were testing an internal change to our routing mechanism and returned a testing message for some of the requests. Unfortunately, in a subset of CDN locations, for customers on our regular network (not HP Edge) that have a proxy in front of Netlify, those test responses were routed through their proxy. That meant that these test responses were cached there and served instead of the corresponding asset.