Index: mod_proxy_core.c
===================================================================
--- mod_proxy_core.c    (revision 1820)
+++ mod_proxy_core.c    (working copy)
@@ -1178,6 +1178,10 @@
                        /* fall-through for non-keep-alive or response parsing didn't finish */
 
                case PROXY_CONNECTION_STATE_CLOSED:
+                       /* user terminate connection and proxy connection is still in CONNECTING mode.
+                        * this happends frequently when backends are slow
+                        */
+               case PROXY_CONNECTION_STATE_CONNECTING: 
                        proxy_remove_backend_connection(srv, sess);
                case PROXY_CONNECTION_STATE_IDLE:
                default: