mod_cluster can't handle local http requests with ws. This causes issues if content needs to be served locally from htpd for HTTP requests. Even proxing an http request, the proxy upgrades that to a ws tunnel. Then if the client makes another http request on their keepalive connection tied to that tunnel, the request is automatically sent on the ws tunnel, even if it does not match a enabled context. This means a 404 is seen from the backend instead of serving the content locally from httpd's DocumentRoot.