I read the solution from this post: https://us.community.samsung.com/t5/Qled-and-Frame/Samsung-Q70T-display-issues/td-p/1841437
From this post, I understand that the HDMI cable test is designed for 2m cables. I am using a 20ft premium certified 4k cable to connect the Q80T 75 inch TV to a Onkyo TX-NR686 receiver (supports 4k, HDMI 2.0 and ARC). I then connect my new Apple TV 4k (Supports 4k, HDMI 2.1) to the receiver. I have both the receiver and the tv set up with ARC (TV supports eARC but receiver only supports ARC). I did this to get the TV volume back to the receiver when clicking around and watching TV apps. The Apple TV resolution is set to 4k, the info button on the TV remote states that the resolution is 4k and most importantly, when I watch a 4k video on Youtube and turn on 'stats for nerds', I get verification that I am watching true 4k frame rate. My problem is that when I connect the apple TV 4K directly to the TV with the 20 ft cable, even though the test is designed for 2m (6ft) it has no problems. Once I pass it through the receiver, the test shows that the source resolution is 720 and fails even though all other identifiers state that the resolution is true 4k. Does the HDMI cable test fail when passed through a receiver or is something wrong with my setup?
Note: I chose not to pass the apple TV directly to the TV and then send the audio signal to the receiver through ARC because my receiver supports Dolby Atmos and ARC does not. I would need to replace the receiver with an HDMI 2.1 compliant receiver in order to continue to use Dolby Atmos.
I'm having the same issue with my Q900ts. When I run the cable test from the 10ft HDMI cable it states my cable needs to replaced, no matter what HDMI cable I use. This is causing an issue with my 8K receiver which thinks my TV is not set up for 8K/60P or even 4K/120P. Is there a fix for this?