Ahh... just got confirmation:

You are correct; regrettably, that does seem to have happened. I'm not totally sure how, but I have a suspicion. The current method of translating your Perldoc formatted manuscript into workable text involves converting it first into HTML. Normally that doesn't include the listings, but in this case maybe they went through the wringer with the text. Unfortunate than none of us spotted it in proof. It didn't happen for December.

What shocked me the most was "converting it first to HTML"!! Gack! HTML is not a useful markup language for generic items!

-- Randal L. Schwartz, Perl hacker