In a recent upgrade to the forums, the way hidden e-mail addresses are displayed changed slightly.
Please note that hidden e-mail addresses are, and have always been hidden from public view.
The change is that previously, if you had elected to hide your e-mail address, it was not shown at all when you viewed your own profile. After the upgrade, hidden e-mail addresses were displayed to the profile owner, but in italics. If your address appears in your profile in italics, it is hidden from other users. (You can log out and view your profile or your posts to verify this.)
Hopefully this clears up any confusion.