you are the expert on camera/RAW Steve not me - I just threw it in in case - didn't really think Exif would make a difference, but was not sure about chroma - thought if that had been changed previously and was now back to default it might be a factor?

also of course in PSP9 you can simply save a jpeg [ and as a jpeg2000 also] rather than run it through the optimiser, would that be different?

be useful to see the file, agreed