Looking through the probe logs, and seeing that your monitor is using EISA bus and works fine without HDR, there doesn't appear to be any issues on the Linux side of things. My guess is that they didn't implement HDR on the monitors side exactly to spec and that's where the problem resides. So, in this sense some monitor specific quirk fixup code is needed on the Linux side of things to get it working properly. If the devs ask any additional steps from you, be sure to do it and provide feedback.