DIAMETER : What action taken by a Diameter node for the loop-backed Diameter message ?

Question

I know Diameter client can re-transmit the request message until it receives the answer message.
But what about when a Diameter node has sent answer message to the last received request from its peer and that's is not received but its peer. In this case, from Diameter client node transaction is not completed since it did not receive answer message but from other node point of view it has responded with answer and transaction is completed.