The current fix for this bug is in simple.el.  This comes with the side
effect that it will not be available in older Emacs versions when CPerl
mode makes its way to GNU ELPA.

The bug is completely harmless, I guess that porting the fix to older
versions isn't worth the effort.  I suggest to just skip the test when
run under Emacs < 28, though this isn't strictly mandatory in the Emacs
repository.
--
Cheers,
haj