I have tried to raise a support case on this but have been blocked by requests for serial number (License key is unrecognised), and the contact a call centre link (as well as the support pages for RDP at the moment) end up in a 404.
When configuring RDP PC client in Windows 10 (v3.9) to use SIP TCP (no proxy registration) and a manual NAT override, the SDP Contact and Origin lines get completely managed. Please see the obfuscated images files from Wireshark, however the issue is also confirmed from the RPD logs.
It looks as if the replacing of test has gone awry. Hopefully this can get to the right people as this is a good product.
welcome to the Polycom Community.
I have forwarded this to Engineering and they believe this is a bug.
I will keep updating this post.
Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.
Polycom Global Services
If official support is required please check how to phone or open a case here----------------