Occasional transient Proxy Errors

(Bug, Investigate , Priority: Medium, Test Status: No automated tests yet , Reported By Justin du Coeur, )
System
Summary: When you fetch a Querki page, you occasionally get a simple "Proxy Error" page. This typically goes away if you refresh.
Internally, we're getting an Apache error, such as:
proxy: error reading status line from remote server IP of Play server, referer: http://www.querki.net/u/jducoeur/alpha-issue-tracking/.3y284r2
Aaron suspects that it involves one end of the connection between Apache and Play closing the connection, and the other not immediately realizing that.
Aaron is going to try to setting proxy-initial-not-pooled, to see if that fixes it.
Later: the frequency of these errors has increased markedly, week of 12/16.