Broadvox one way audio re-invite issue

[JointTech]

I've been having trouble with random one way audio with my Broadvox SIP trunk. They put me in test mode and then sent the pcap file and said :

Attached is a copy of the capture taken during interactive testing. Currently, we are seeing the RTP (Media Stream) being negotiated for port 9004 in the SDP of the 200 OK. The media stream is then sourced from port 29600 but eventually begins souring from port 9004. Any changes to the media stream need to be indicated with a Re-Invite. Please examine your internal network.

Wondering if anybody knows what setting I have wrong. Does Supports Re-Invite need to be Checked in the VOIP provider setup?