Retested here with German and French accented characters, all is fine.
Seing the image with the main menu having the correct accented characters, and CB having the wrong ones, I have the impression that your site character encoding have changed over time without correct update in the database, or your browser is not in sync.
- Did you check that your browser charset selection is "automatic" ?
- Did you try to update the profile with frontend user edit with correct accented characters ?
If both of this don't work, please PM me your site URL and a login to see the html code generated...