[Serusers] Record-route:/Contact: conflict?

I've got a packet that looks like: # U 2003/02/24 07:56:52.503535 216.87.144.203:5060 -> 216.87.145.22:5060 SIP/2.0 200 OK. Via: SIP/2.0/UDP 216.87.145.22:5060;branch=z9hG4bK-ng5tokyx448r. From: "snom man" <sip:4695461245@augustvoice.net>;tag=8u6ju8wxuc. To: <sip:2143357976@augustvoice.net;user=phone>;tag=3CBB0360-532. Date: Mon, 24 Feb 2003 13:56:43 GMT. Call-ID: 3c267202b6a8-lgseu8olovlp(a)216.87.145.22. Server: Cisco-SIPGateway/IOS-12.x. CSeq: 2 INVITE. Session-Expires: 7200;refresher=uac. Require: timer. Allow-Events: telephone-event. Contact: <sip:92143357976@216.87.144.196:5060;user=phone>. Record-Route: <sip:2143357976@216.87.144.203;ftag=8u6ju8wxuc;lr>. Content-Type: application/sdp. Content-Length: 209. . v=0. o=CiscoSystemsSIP-GW-UserAgent 7543 5694 IN IP4 216.87.144.196. s=SIP Call. c=IN IP4 216.87.144.196. t=0 0. m=audio 16632 RTP/AVP 0 100. a=rtpmap:0 PCMU/8000. a=rtpmap:100 X-NSE/8000. a=fmtp:100 192-194. The main thing to note is the packet is sent to a SNOM phone from my PROXY server. Curious, when the SNOM phone responds it is responding to 216.87.144.196, which is my GATEWAY. My GATEWAY is configured to only listen to the PROXY server, so it drops the packet. In the packet above, the Record-route line indicates that 216.87.144.203 should be responded to, which is my PROXY. Also in the packet above, there is a 'Contact:' line that indicates the GATEWAY at 216.87.144.196 should be contacted. Obviously the SNOM phone is getting the address from the Contact: line (or maybe the SDP) rather than the Record-route: line. Is it doing so incorrectly, or do I have a bug in my GATEWAY, or does the PROXY need to strip out the Contact: line?