Display Color Management not working?

Because of course it all depends … on a number of things. 

DCM only tells Premiere to check the ICC profile in use by the monitor, and deliver an appropriate image for that ICC profile. Which of course doesn’t mean that it will always deliver the correct image … at least, what you expect as the correct image.

Because depending on whether that monitor is actually correctly calibrated in place in your room, how or what settings you have made in the monitor and/or GPU control panels, the media color space, and your settings in the full (and now quite extensive) CM options in the Lumetri panel Settings tab, where all CM settings ‘live’ now … something can easily be “off”.

So we can't give you an answer unless we know a ton more data … your OS/CPU/GPU, media and its color space, your entire Settings tab of CM settings … and what you are viewing in/on outside of Premiere. Then we can actually give intelligent advice.

And QuickTime player on any Mac that does not have Reference modes that are currently set to HDTV … will not ever give a correct Rec.709 image on the display. Which is a pain up the ying yang.