PDF/X-4:2010 Preflight Warning: Colour separation for special colour are inconsistence

Hi!

Maybe the community can help me with this:

When exporting a InDesign-document to Adobe PDF/X-4:2010 for prepress/print, I get a warning about color separation inconsistency. When checking this out, it points to the ”cutting-marks” and to the document-info of the PDF (this is all outside the printing-area). It also warns about the system font Helvetica. 

I have never seen this warning before. And even more strange: When I do a preflight of the PDF in smaller chunks of pages, everything is ok. The PDF-document have 336 pages.

Translation, screenshots:

Registreringfärg = Special colour

Övertryck av/på = Overprint on/off

I work in:

Adobe Acrobat, version 2025.001.20841 (Creative Cloud Standard)

Adobe InDesign, version 21.0.1 (Creative Cloud Standard)

Mac Studio Sequoia 15.6.1

/Marta