Modification Detection and Prevention Certificate Application Breaks PDFA/3-u Standard
When applying a Modification Detection and Prevention certificate to a PDF/A-3u file Acrobat Pro DC adds DigestLocation, DigestMethod, and DigestValue entries to the signature references dictionary. That's not permitted by the PDF/A-3u standard. Thus it breaks conformance.
Certifying PDFs in this way and complying with the PDF/A-3u standards both are part of our larger goal of long-term preservation.
Joachim Seifert commented
I agree - a work-around is using signatures but semantically a certification is more apt, as you certify that the document is valid and can be archived