Just a notice�� the style \startoverprint� should be probably in future versions too, or how to overprint two elements and how to knockout the next one? Is it possible? (In one file could be a lot of such cases needed.)

In case of \setupcolors[intent=overprint] is the problem in the fact that preflight says that all text is "gray object overprinted" and that is against the standards. I have simply one test page with one article of black text. Everything goes fine except the fact of non-embedded profile and the fact that text is considered like a gray scale object.

In case you could try to generate one pdf with such settings I could test them in Acrobat.