Could you post the relevant bits of your router (are you using any of @xdn/ packages?) and the path to the resource? If there is any sensitive data please DM it to me.
Ok, glad to hear you solved it. Also note that our @xdn/next package, if added through .use, will also insert a route for '/_next/static/:path*' pointing to the static backend. If you need to work around this, before .use rule add your own rule for '/_next/static/:path*' and route those requests to origin.