Videos go dark on external display (strange problem!)

[Inutopia]

Really strange problem I'm having.

Videos go much darker, and have the contrast turned up when I stop moving the mouse. I first noticed with full screen youtube videos, and the difference is stark, it's almost like the colour profile on the monitor is being switched.



Since first noticing this I've also made the following observations: It happens with quicktime vids, even if they are not full screen. It only happens with Youtube when it is full screen. It doesn't happen with my laptops internal display, only the external.



I tried to record it with screen-record on Quicktime, but amazingly, it doesn't happen when that is running! Hilariously, it does happen with the resulting video The only way I'm able to show it is by recording with my phone, which I've uploaded here:

https://imgur.com/a/4cp26Rr

Im using a 14 inch M1 Pro Macbook and a 32 inch 4k external connected over displayport (caldigit TS3+)

Running Monterey 12.2



Anyone seen anything like this before? I've had no luck googling it as yet!

 

[ed.]

It might have to do with HDR. I've never experienced anything similar, but I have my MacBook Pro hooked to an external 4K HDR monitor and when I tried out the HDR on the monitor I've noticed that there's something like a ì quick color profile switch just before the HDR content starts. So maybe your system is trying to set up HDR and something's not working?

 

[Inutopia]

It might have to do with HDR. I've never experienced anything similar, but I have my MacBook Pro hooked to an external 4K HDR monitor and when I tried out the HDR on the monitor I've noticed that there's something like a ì quick color profile switch just before the HDR content starts. So maybe your system is trying to set up HDR and something's not working?

I see what you mean, but the monitor is not HDR capable. At any rate it wouldn't happen in a windows as you can see in the video, as that would necessitate the display being in two colour spaces at once!