I managed to find a fix for the broken gamma, and nvidia dithering in windows 1903: you need to go to Task Scheduler > Microsoft > Windows > WindowsColorSystem, and delete the task called WindowsColorSystem Calibration Loader.
This topic was modified 5 months, 1 week ago by A.ces.
I can confirm that disabling the “WindowsColorSystem\Calibration Loader” task (even if “Use Windows display calibration” in Windows color management settings wasn’t enabled to begin with, which is interesting) and logging out/back in solves the severe banding (but it may be back if changing the calibration, in which case the log out/in procedure needs to be repeated). We’ll have to wait for a proper fix from MS. I will probably add automatic disabling of the task upon installation in a DisplayCAL update to mitigate the problem until a proper fix comes in the form of a Windows 10 update.