I've had reports from some of my users that they get no audio on random incoming calls. When they answer the call, the recipient cannot hear anything, and the caller is disconnected.
I took some debugs and noticed in the failing calls that the SIP invite and the c line of the SDP have IP addresses that do not match. Debugs of successful calls have IP addresses that both match in SIP invite and SDP.
Here is the output I gathered (some values are masked to protect the innocent):