structures jump out of math set with $$

[u-fischer]

When $$...$$ are used for display math, paratagging is not disabled (differently to e.g. equation) and structures jump out of the Formula:

\DocumentMetadata{testphase={phase-III,math},pdfversion=2.0}
%\input{regression-test}
\documentclass{book} 
\begin{document}
\begin{equation}
x=1\quad \parbox{3cm}{text 1}
\end{equation}


$$
y=1\quad \parbox{3cm}{text 2}
$$

\end{document}