Just wondering if you found anything for this yellow desaturation issue ? Is there a dedicated discussion somewhere about that topic ?
I did some tests myself to understand more precisely how and where this happens, using InverseODTRec709 -> InverseRRT -> RRT -> ODTRec709 on image with saturated yellows, eg. from logos / titles (from what I recall the "Global desaturation (inverted)" in the InverseRRT can produce out of AP1 yellows that get lost by the clamp right after), but didn't have the time to go any further.
From what I understand the RRT/ODT Rec709 can't produce yellow with maximum saturation in the first place so we cannot expect the Inverse process to preserve all that but maybe there is a way to have a more controlled desaturation ? Also I find it interesting that this is mostly visible only for yellows.