Xfinity Stream App video suddenly pausing/chopping

After working perfectly for over a year, my Xfinity stream app (through Roku device) suddenly became continuously choppy (video only).  This occurs only with the Xfinity stream App.  Netflix, Prime, Apple TV, etc all work fine with the 4K HDR 60 fps setting.  I have restarted the app, then removed and reinstalled but app with no luck.

If I change the video display on the Roku from the automatically selected  4K HDR 60 fps to 4k 60fps, the video becomes smooth again.    Any suggestions?  thanks