Is there some public bug that's already been logged for this ? I think I might be hitting a similar issue with my own ProRes integration.

A small finding: The issue seems to appear only with kCVPixelFormatType_64ARGB pixels and switching to kCVPixelFormatType_4444AYpCbCr16 pixels seems to fix the issue (and I think it is more performant )

I have received a notification from the Apple byg system that it is fixed in the latest beta version of osx ( I have bot verified it yet ).