un transport with max-sockets local_port is set to zero on reused socket after ACK

[yulianoifa-mobius]

Hi
when UAC is used with un and max_socket , the sipp sets local_port to zero after non provisional response is received/ack is sent.
Please see pcap attached ( zipped ). For every socket opened first 2 calls works fine , however the third one after 180/200/ACK i sent with port zero in contact and via. As result the server is not capable to send response back and gets udp error.
sip.zip