[SR-Users] Kamailio multihomed - BYE problem

Hi, I'm having a problem with routing of BYEs in my multi homed Kamailio. My setup is a Kamailio v4.1.5 with two NIC (172.20.11.0 & 192.168.10.0) and three phones. Two phones (1 for each LAN) are in a group, so using alias_db I can call them in parallel mode. Caller is on 172.20 network...When I answer from phone on 192.168.10.0, RTP is ok ... but on BYE Kamailio replies with 404 Not Here...and the RURI of BYE has the IP of Kamailio instead the IP of the callee.When I answer from phone on 172.20.11.0, RTP is still ok and also BYE is managed correctly from Kamailio and the RURI of BYE has the IP of the callee. How can i solve this issue?Many thanks