[SR-Users] Callee BYE routing issue

Have an issue with BYE routing in a lab setup, any suggestions on what I should be looking at? Topology: UA1 <-> NAT device 1 <-> Proxy1 <-> Registrar/B2BUA <-> Proxy1 <-> NAT device 1 <-> UA2 All UA to UA calls flow through B2BUA. All IP’s are public except for UA1 and UA2. -Both endpoints can call each other. -If the caller hangs up first, BYE is routed properly. -If the callee hangs up first, BYE causes proxy to send 478. On calls where BYE results in 478: if(!isdsturiset()) { ……….…………………….not executed handle_ruri_alias() } return; Example issue call: UA2 to UA1, UA1 hang-up. Apr 10 00:31:28 edgedev /usr/local/sbin/kamailio[5317]: ERROR: {1 2 BYE 24dc84a4592515245177483c2a657042@B2BUA_IP:5160} *** cfgtrace:dbg_cfg_trace(): request_route=[DLGURI] c=[/usr/local/etc/kamailio/kamailio.cfg] l=540 a=16 n=if Apr 10 00:31:28 edgedev /usr/local/sbin/kamailio[5317]: ERROR: {1 2 BYE 24dc84a4592515245177483c2a657042@B2BUA_IP:5160} *** cfgtrace:dbg_cfg_trace(): request_route=[DLGURI] c=[/usr/local/etc/kamailio/kamailio.cfg] l=532 a=24 n=isdsturiset Apr 10 00:31:28 edgedev /usr/local/sbin/kamailio[5317]: ERROR: {1 2 BYE 24dc84a4592515245177483c2a657042@B2BUA_IP:5160} *** cfgtrace:dbg_cfg_trace(): request_route=[DLGURI] c=[/usr/local/etc/kamailio/kamailio.cfg] l=540 a=2 n=return ……….. Apr 10 00:31:28 edgedev /usr/local/sbin/kamailio[5317]: ERROR: {1 2 BYE 24dc84a4592515245177483c2a657042@B2BUA_IP:5160} tm [ut.h:245]: uri2dst2(): bad_uri: [sip::;transport=] Apr 10 00:31:28 edgedev /usr/local/sbin/kamailio[5317]: ERROR: {1 2 BYE 24dc84a4592515245177483c2a657042@B2BUA_IP:5160} tm [t_fwd.c:1732]: t_forward_nonack(): failure to add branches Apr 10 00:31:28 edgedev /usr/local/sbin/kamailio[5317]: ERROR: {1 2 BYE 24dc84a4592515245177483c2a657042@B2BUA_IP:5160} *** cfgtrace:dbg_cfg_trace(): request_route=[RELAY] c=[/usr/local/etc/kamailio/kamailio.cfg] l=275 a=24 n=sl_reply_error Apr 10 00:31:28 edgedev /usr/local/sbin/kamailio[5317]: ERROR: {1 2 BYE 24dc84a4592515245177483c2a657042@B2BUA_IP:5160} sl [sl_funcs.c:401]: sl_reply_error(): stateless error reply used: Unresolvable destination (478/SL) Apr 10 00:31:28 edgedev /usr/local/sbin/kamailio[5317]: ERROR: {1 2 BYE 24dc84a4592515245177483c2a657042@B2BUA_IP:5160} *** cfgtrace:dbg_cfg_trace(): request_route=[RELAY] c=[/usr/local/etc/kamailio/kamailio.cfg] l=277 a=2 n=exit 2020/04/10 00:31:28.625060 NAT_Device_IP:57808 -> Proxy_IP:5060 BYE sip:398@B2BUA_IP:5160 SIP/2.0 Via: SIP/2.0/UDP UA1_IP:52884;branch=z9hG4bK-524287-1---43b5f31829f20952 Max-Forwards: 70 Route: <sip:Proxy_IP;lr=on;ftag=as78671fd9;did=b1b.a27> Contact: <sip:399@UA1_IP:52884> To: "Dan Test" <sip:398@B2BUA_IP:5160>;tag=as78671fd9 From: <sip:399@UA1_IP:52884;rinstance=705e0af5f4be485c;alias=NAT_Device_IP:~57808~1>;tag=64f4b712 Call-ID: 24dc84a4592515245177483c2a657042@B2BUA_IP:5160 CSeq: 2 BYE User-Agent: xxxxxxxxxxxxxxxx Content-Length: 0 ######################################### For comparison, here is a BYE from another test call: UA1 to UA2, UA1 hang-up. This BYE was routed correctly. 2020/04/10 00:44:02.688608 NAT_Device_IP:57808 -> Proxy_IP:5060 BYE sip:398@B2BUA_IP:5160 SIP/2.0 Via: SIP/2.0/UDP UA1_IP:52884;branch=z9hG4bK-524287-1---ce36df02e8a80a48 Max-Forwards: 70 Route: <sip:Proxy_IP;lr=on;ftag=9078f232;did=49e.8c01> Contact: <sip:399@UA1_IP:52884> To: <sip:398@B2BUA_IP>;tag=as5874901f From: <sip:399@B2BUA_IP:5060>;tag=9078f232 Call-ID: 103104NGU1NjkxNGZkYmM4MzA3Y2FkMzY1OGNkZTZmMTMyZDU CSeq: 3 BYE User-Agent: xxxxxxxxxxxxxxxx Authorization: Digest username= xxxxxxxxxxxxxxxx Content-Length: 0 -dan