PDF export to grayscale not working (many placed PDF files)

[losgelaufen]

Hello there,

i have a 54+4 page brochure that i want to export as a grayscale PDF. I have to say that i haven´t had to export an PDF from it since Publisher 1.8 (but then it worked fine). 
98% of the placed content are always the same. Just the text has changed of course.
Now i get the error "Error at the export in: /Users/..." 

Just for the "fun" i created a new document and copied every page as a single page in this new document and tried to export it as grayscale... and it worked.
Then i created another new document and copied every page in this new document so that i have the 58 pages again. And the export failed again.

I have placed many PDF files in this document with different PDF versions. So my suspicion was that publisher has a problem with many placed PDF files with different versions.
That´s why i created as my last step a new 58 pages document. And started to place those PDF files new with importing. And as soon as i had placed 6 PDF files i got that error when i tried to export as a grayscale.

My operating System is macOS Catalina 10.15.7 and i am using Publisher 1.9.1

 

[Pauls]

Could you upload the file here please.
I will need the placed pdfs as well so can you also post a saved package