Not saying what you're saying here is incorrect, I'm just adding to it;
Sure, I have seen bugs with HDR here and there (obviously). In my experience, when colors and/or contrast is blown out, that is because whatever game or video you're playing is rendering in HDR mode but your monitor somehow bugged out and are actually displaying in SDR mode.
Displaying video or games in active HDR mode on a display in SDR mode with exactly do that, blow everything out like crazy, because so much of the spectrum is missing for displaying the HDR correctly (because the monitor actually is running in SDR).
To fix this, simply disable and enable HDR again in Windows.