I've updated the firmware on my UHD722 and replaced all the HDMI leads with Audioquest Cinammon (which are 18.2 rated at the lengths I use (< 3m) but this problem still exists even on full HD. (I got so fed up that I leave my Sky Q and Oppo 203 running 1080p until I want to watch something in 4k when I'll switch for the duration of the program and then switch back).

I get the pink film issue probably a couple of times a week on power up. Never had a problem with my HD621. I also get the occasional illegal format msg on my LG OLED.

The cure is always to pull the HDMI cable at the TV end (it's the most accessible) and re-insert. I tried reporting to M via their website and had zero response. Right now I'm seriously considering going Trinnov.

Meridian Owner since 1991