OK, I think @dacoop2 is on to something. I originally reset my HR 54 & C61K to try and resolve the video stuttering from last week's Man U-Chelsea match. That did nothing. Starting watching the Man City-Spurs match on 105 today and of course same issue: Player movements not smooth and neither is the ball when following it in the air. One thing I did not do earlier was turn OFF HDMI Deep Color. I turned it off for that HDMI Input & restarted the B6P. I could see a difference right away in the feed. It was smooth, no stuttering. However there was a large notification message at the bottom of my display that said an HDR signal was detected and the TV needed to be restarted and the only option was to select "restart". I could not get rid of message of but decided to do nothing; I wanted to watch the video feed for framerate issues and it was smooth. After about a minute, the B6P rebooted itself back to HDMI Deep Color ON. After the reboot, the framerate issues were gone. Then I went to the local NBC channel broadcasting the match and immediately back to Ch. 105. The framerate issues were back. I then repeated the HDMI Deep Color settings process that I mentioned above^. The framerate issues were again gone. Anyone with LG 4K set can try this workaround to see if gets rid of the stuttering. It's a PITA to do this every time but maybe help get more input on what the issues are.