I recently ran into an issue where I needed to monitor a reverse proxy which proxied requests to several internal servers (aka load balancer).
The issue was that all requests going to this specific virtual host were proxied to the balancer members configured within the virtual host, including requests to /server-status.
The fix is to add the following line above the ProxyPass directive:
ProxyPass /server-status !
This directive tells mod_proxy to not proxy requests with a path of /server-status and results in a correct response from mod_status.