It seems like they didn't change your previous preferences but rather added a new one and changed how they interpret preferences as to what is displayed. If you look at your list of e-mail addresses, it will let you choose who to share it with if it should be shown on timeline. Previously I had a real e-mail address that was being shared with friends and another real address that was for 'only me'. When I looked at m…
FWIW, I had my real email addresses showing before this weekend and when I checked this morning, the only email address that was being shown was the @facebook.com one. My other 2 email addresses (one visible to each of my friends and one only to a close few) were hidden from my timeline. Shady!!
It's safe to assume that the vast majority of users fit this case: signed up with an email address, never added a second one.
Since it affects this use case.. I'm going to posit that this is quite widespread.