I had this problem too... and fixed it in about 10 min. I searched the internet for this problem and found many forums with pretty much the same resolution... REPLACE TV. I find it interesting that in almost every single case I read over the last 24 hours... no one... absolutely no one recommended a simple Problem Determination (PD) procedure to quickly determine if the issue was in the TV or outside the TV.
Supposedly people spoke to techs on the phone, which in most cases are reading from a tech manual... or try to dial in and update TV firmware remotely... what I didn't see or read is where someone actually had a repairman look at it.. or did actual PD to eliminate issues with cables or devices connected to the TV.
My Curved Samsung UN55JU6700 among several other devices... is connected to an Xfinity HDR and through HDMI cables. So.... the first thing I wanted to do was to see if the problem went away if I changed channels... it did not. Then, would the issue move when using another HDMI source...
I turned on my APPLE TV and switched to that as the source. I immediately noticed that the issue appeared to go away... so for grins, I tried my DVD player... and still the problem did not return...
Now I know its either the HDMI cable feeding the signal or the xFinity box itself... so I tried a different cable and the problem did NOT go away this time... Now I'm highly suspecting the Xfinity DVR device. I powered off the HDR but the problem still remained ... No I'm thinking Im going to have to spend an hour on the phone with a tech that knows less then I do... or spend an hour or two at the Comcast store waiting for a replacement DVR. SO BEFORE I did that, I tried one last PD step ... I decided to UNPLUG the DVR and let it do a complete POWER ON RESET ... in case something got hosed during the last firmware update.... 10 minutes later... my SAMSUNG is working flawlessly once again. DONE, FIXED (at least in my case).
So ... if your having this issue... BEFORE panicking from all these doomsayers on the net... that in many cases sell or repair TV ... try some simple PD ... hopefully you'll be lucky like I was.