I've had a polycom HDX 8000 running on version 220.127.116.11-13047 and it worked really well for me. I dial in to it with quite a few different units and my own gateway unit. Recently though I upgraded to 3.1.0-23277 and now sometimes when my gateway or a Sony PCS is connected to the HDX, the screen on the Polycom is black. This is 100% not a network issue because this unit worked fine with the older version and I've done extensive packet capture to make sure that data is getting sent to the Polycom.
The device is on a public IP address and I am making H323 calls to it. The H323 q931/h245 call setup/media negotiation look fine and logical channels are opened both way. I see data travelling in both directions, but the video on the Polycom side is randomly showing up as blank at times. I looked at the logs and noticed this: