Hi Joe, Thank you for the response,
The project was shot on the C300 MK III, in Cinema RAW Light 10-Bit.
I did use the color mask in FCP. How do I use the HSL with Luma enabled? Interested in this, the color mask is definitely the problem. The ProRes export looked fine. it was just the MP4 export and uploading to vimeo where I saw the problem.
I’ll also try your work around.