The whites of the ProRes 422 are actually higher than they should be as well (like 8% higher when monitoring in FCP) so the whole spectrum is kind of stretched). Is there a solution to this if this is caused by wrong IRE information?
When exporting to ProRes 4444 the black level looks fine so it must be the rendering to ProRes 422 that is the problem. Rendering to ProRes 422 (HQ) is crushing the blacks as well.