improve paratagging if nested boxes are involved

[u-fischer]

\RequirePackage{pdfmanagement-testphase}
\DeclareDocumentMetadata
 {}

\documentclass{article}
\usepackage{varwidth}
\usepackage{tagpdf}
\tagpdfsetup{paratagging,paratagging-show}
\AddToHook{para/begin}{\typeout{begin}}
\AddToHook{para/end}{\typeout{end}}
\begin{document}

abc \parbox{3cm}{zzz} cde

\end{document}

gives warnings about nested mc.

The question is if this should be resolved in the hook code, or in the box definitions ...