diff --git a/sippy/SipTransactionManager.py b/sippy/SipTransactionManager.py
index 54b17bac2..2b8818de0 100644
--- a/sippy/SipTransactionManager.py
+++ b/sippy/SipTransactionManager.py
@@ -429,11 +429,6 @@ def incomingResponse(self, msg, t, checksum):
                         t.resp_cb(msg, t)
             else:
                 # Final response - notify upper layer and remove transaction
-                if t.resp_cb != None:
-                    if t.cb_ifver == 1:
-                        t.resp_cb(msg)
-                    else:
-                        t.resp_cb(msg, t)
                 if t.needack:
                     # Prepare and send ACK if necessary
                     fcode = msg.getSCode()[0]
@@ -479,9 +474,15 @@ def incomingResponse(self, msg, t, checksum):
                         t.ack_checksum = checksum
                         self.l1rcache[checksum] = SipTMRetransmitO()
                         t.teG = Timeout(self.timerG, 64, 1, t)
-                        return
                 else:
                     self.l1rcache[checksum] = SipTMRetransmitO()
+                if t.resp_cb != None:
+                    if t.cb_ifver == 1:
+                        t.resp_cb(msg)
+                    else:
+                        t.resp_cb(msg, t)
+                if t.state == UACK:
+                    return
                 del self.tclient[t.tid]
                 t.cleanup()