Xfinity Stream, specifically NBC, video issues with Apple TV 4K

Xfinity Stream works fine with Apple TV 4K except for the NBC channel. The NBC channel video goes into slow motion while audio continues in real time with the disconnect/synch growing as time continues. No other channels have this issue, just NBC. I do not experience this issue if I use Xfinity Stream independent of Apple TV 4K. I have tried re-starting the Apple TV 4K. I have tried deleting the Xfinity Stream app from Apple TV 4K and re-loading. Neither of these "fixes" worked. Can someone please help with this issue?