I sympathise with the Samsung and Sony 4K TV owners out there. I recently had to replace my TV and wanted to go to a 4K one. I downloaded some 1080p and 4K footage from my P3Pro onto an extremely fast USB stick and went to one of the biggest TV retailers here in the UK. They allowed me to play the footage on several makes and models and I found that it was only the Panasonic CX802 series played them back flawlessly.
None of the Sony ones would play back the 4K footage (they did do with the 1080p footage) - I've since read on other forums that this is a well known issue with Sony 4K TV's. The Samsungs, including the 8K model either didn't play the 4K at all or, in the case of the 8K TV played the 4K stuff but there was quite a lot of distracting flickering of the image.
So I settled on a 55" Panasonic CX802B and it plays both my Phantom and GoPro 4K footage perfectly.
Something is clearly wrong with this. I have a 2 year old Samsung 4k with their latest Evolution box and it plays my P3 and I1 4k files without any lad or stutter. I find it impossible to believe that Sony's and Samsung's latest TVs on the floor of a large retailer will not play 4k files. That just does not sound right.
Maybe the floor salesmen had something set improperly?