Yes, this page is deliberately public, and it is shown in the case that the endpoint server is turned off or unreachable from mainstream reverse proxy server. There is no need to report it to our security team and if you do we'll just ignore the report.

Proxy Error

The proxy server received an invalid response from an upstream server.
The proxy server could not handle the request

Reason: Error reading from remote server
back to mainstream page.

httpd/h2 (Slackware) Server at port 80