Bug is confirmed by W.C.A. Wijngaards, he has provided a fix:

Index: iterator/iter_delegpt.c
===================================================================
- --- iterator/iter_delegpt.c   (revision 3256)
+++ iterator/iter_delegpt.c     (working copy)
@@ -147,7 +147,9 @@
 {
        struct delegpt_addr* p = dp->target_list;
        while(p) {
- -             if(sockaddr_cmp_addr(addr, addrlen, &p->addr, p->addrlen)==0) {
+               if(sockaddr_cmp_addr(addr, addrlen, &p->addr, p->addrlen)==0
+                       && ((struct sockaddr_in*)addr)->sin_port ==
+                          ((struct sockaddr_in*)&p->addr)->sin_port) {
                        return p;
                }
                p = p->next_target;