i have new NUC6CAYH. Latest bios 0045, latest HDMI firmware 1.72. Current Windows 10 Home. HDMI 2.0 cable.
When I set the monitor to turn off after x minutes (windows settings - power a sleep), the monitor turns off for only 1 second and then switches on again (black screen 3 second). Then again 1 second off and on. And over and over again. When I move the mouse, the monitor turns on.
My guess? This likely means that the monitor never saw the sleep request and it is simply reacting to the output being shut down by the NUC.
I gave up on their monitor sleep support a long time ago. The latest 7th gen NUCs have the same monitor sleep issues that the 4th gen NUCs had. They blame the monitor every time. Baloney! I simply disable Monitor Sleep; it wastes a bit of power, but at least it works as it should.
Reinstall Windows and change HDMI cable - no change.
Monitor sleeps for 1 second and turn on the black screen (3s check hdmi signal) and again.
Same monitor, another computer, everything ok. Problem only with NUC.