PAC 2 Error
Suspects key is set to true
PDF/UA > Metadata and Settings > Document settings > Tag suspects
ISO 32000, Table 321 and Paragraph 220.127.116.11.1: Reading order has been properly determined, but the Suspects key indicates otherwise.
In Acrobat Pro: Open the Content pane > Right-click the root > Select Edit Document Catalog > Expand the Document Catalog > Expand the Mark Info dictionary > If the Suspects Key is incorrectly set to True, either set it to False or delete it.
Video version of this suggestioin: