Thanks to one of our customers pointing this out but we’ve recently been pointed to this article:
https://www.colourphil.co.uk/printing-mac_colour_problems.shtml
… which details a known issue with newer versions of MacOS and older 32 bit versions of Adobe products such as CS4, etc… where the colour rendition is out of what and appears to be a printing problem when really it’s a driver/OS issue.
So, if you are using a MacOS and are getting some really odd problems, it’s worth reading the linked article above and add it to your troubleshooting list in case it’s relevant.