A page whose /Annots is an object of its own keeps its dictionary when a
later revision adds a signature widget or a comment: only the array
changes. That array fell through to "other changes", so countersigning
such a document (as many signing services do) turned every earlier
signature invalid, including PdfCraft's own second signature.
A changed array that was a signed page's /Annots is now classified like
an inline /Annots: by the annotations it gained (signature, form fill or
comments), under the same DocMDP rules.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>