I'm not sure where the answer would lie, since I've never had to deal with accented characters in perl. But

perldoc perlunicode

may be a good place to start.

I recall a great deal of traffic about utf8 and regular expressions on p5p, so this may be an area where it's important to make sure you're using a recent (recentest?) perl.

Which perl version just got installed?

It may have known bugs (to someone else, that is, not me.)

I realize this isn't a very helpful answer, but I hope this points you to something that does help...
--
Mike