It works when there isn't any httpd... That looks like a bug could you please create a JIRA for that.
It looks like an error once the httpd is started and then stopped and it seems to remain until httpd is started.
Yes - the application host was not able to connect to one of the proxies listed in the proxy-list attribute. Once I removed the broken proxy, the :read-proxies-configuration succeeded.
I'll file a JIRA ticket for that. Thanks!