It's been a few days, but...

That used to be annoying when it was just an error message, but with recent Emacs it also scrolls the window, so in cperl-mode each time I press "m" or "s" the Emacs window scrolls in a random direction.

A recent Emacs bug report #47549 prompted me to revisit that issue, and eventually I've been able to reproduce the scrolling. I've submitted a patch, and the Emacs maintainers have merged it into the master branch.

So, the current cperl-mode.el from the Emacs repository should no longer jump around.