I’m not really sure how to diagnose whether this is a hardware or software issue. I have one of the new 2020 MacBook Airs and I’m outputting via an Anker USB-C to HDMI adapter to a TCL 6 Series 4K TV.
Everything looks good and works and I can output 4K @ 60Hz (took me a while to figure out I could only get 60Hz if I forced the TV to use HDMI 2.0 for that input instead of auto-detect, but I digress), but when I display video in full screen from the Apple TV app or Quicktime player and it’s letterboxed, the letterbox is pink instead of black and the rest of the image has a slight pink cast to it as well.
Moving the mouse to bring up the UI snaps the letterbox back to black and the discoloration of the image clears up, but as soon as I let the UI hide again it snaps right back to pink bars.
Anyone got any theories? I don’t even know how to test if this is a hardware or software issue or really where to begin troubleshooting at all.