Multiple monitors on Intel NUC NUC7i7BNH. I have a brand new LG OLED55C8PLA TV attached to the NUC's HDMI port, and a regular monitor attached to another HDMI port using the USB-C interface.
Both the TV and the monitor are running at 1920 x 1080p at 59/60Hz. The TV is attached to a Denon AVR-4306 surround amplifier with HDMI video/sound input with straight-through signal.
On the NUC - using the Intel graphics software - I can *only* select cloned/duplicated displays such that the image is displayed (flawlessly) on both the TV and the monitor. I am not able to select the TV as the single output. When doing that, both screens blank, and after a while (10-20 seconds), the cloned image appears on both screens. In cloned mode, everything work as expected: full 5.1. surround sound through the Denon amp, and a perfect image on the TV. But, obviously, I would like to de-attach the monitor and only watch the TV screen. If I simply remove the cable to the monitor, output from both screens are gone. The really odd thing is that when I first attached the TV with a monitor, everything worked as expected - single display, surround sound etc. Then I re-booted the NUC and the Intel driver notified me that the TV was able to run at a 3840 x 2160 resolution, and whether I would like to turn that on. I did, and that's when the problems began. Regardless of how the displays are configured, I am always only able to use cloned displays - never just the TV as the single output. Any suggestions are highly welcome.