Deleting reply items before post-proxy

[Eddie Stassen]

Could someone please explain to me if there is any specific reasoning 
behind the following lines right in the beginning of  proxy_receive() in 
proxy.c? (version 1.1.7, similar code in event.c in  2.0)
     /*
         *      Delete any reply we had accumulated until now.
         */
        pairfree(&request->reply->vps);

I was trying to get rid of my 'post-proxy-authorize' dependency and 
found that any attributes added during the authorize stage are removed 
when the proxy reply  is received.  Surely this is not intended 
behaviour as further down in proxy_receive() we have the following lines:
        /*
         *      Add the attributes left in the proxy reply to
         *      the reply list.
         */
        pairadd(&request->reply->vps, request->proxy_reply->vps);

Removing the initial pairfree() gives me the behaviour I expected, i.e. 
add some stuff during authorize, proxy, then combine  reply and 
proxy_reply items before responding.  Am I missing something?

Eddie