bug#35284: 12.1.1; new verbatim environment wrongly commented out

[jfbu]

Emacs  : GNU Emacs 26.1 (build 1, x86_64-apple-darwin13.4.0, Carbon Version 157 
AppKit 1265.21)
 of 2018-06-18
Package: 12.1.1

(my elpa has some patches I think from git repo, but they should not affect 
this)

Consider this source

\documentclass{article}

\begin{document}
% This is a comment
\def\foo#1{foo}
% another comment
\end{document}

Select the three lines delimited by the document environment

Hit C-cC-e verbatim

Result:

\documentclass{article}

\begin{document}
% \begin{verbatim}
% This is a comment
\def\foo#1{foo}
% another comment

% \end{verbatim}
% \end{document}

Regards,

Jean-François