@mclingo
As I said the first time I saw this, I think that desaturation corresponds to the lack of conversion to Rec.709 or DCI-P3. I posted a shader
here to do that conversion, try it and let me know what you think. The shader doesn't do gamut mapping so this should ideally be done with a DisplayCAL 3DLUT, but you need madVR v0.92.16 for it.