> Hence you should return a 500 as this signals the mod_proxy code that the
> backend is broken and should be put in error state.
> A 502 does not put the backend in error state (as you found out).
>
> Regards
>
> Rüdiger
>

I didn't realize this was the case - marking it in error inside 
ap_proxy_http_process_response would definitely be redundant! Thank you 
very much for catching it (and explaining this to me). I have updated 
the patches and bug report and attached the updates for reference.

--
Daniel Ruggeri