Missing Contact header in VQ RTCP XR messages (x.73.0.50)

[oliv]

Hello,

I've discoved vq-collector (see https://github.com/pbertera/vq-collector), a tool that let me collect VQ RTCP XR messages. It seems very useful.

When collecting SIP PUBLISH messages from Yealink x.73.0.50-enabled T28P or T20P phones, I'm getting:
2017-02-27 13:23:11,191 ERROR Received fatal exception: 'contact'

When collecting SIP PUBLISH messages from Yealink x.81.0.25-enabled T27P or T29G phones, I'm not getting any such error and logged data seems fine.

Using tcpdump, I compared SIP PUBLISH messages. In failing case, I could not find any SIP Contact header while this header is present when things work OK.

Does it make sense to have a phone sending VQ RTCP XR with missing Contact header, from SIP compliance point of view ?
If negative, how can I make sure such Contact be included in VQ RTCP XR messages ? Any config option or firmware release ?

Best regards