I'm not sure if this is a bug, but on the Facebook Stack Overflow homepage the elements in the right bar aren't all facebook-specific. My favorite/ignored tags cover all of SO. The recent tags are specific to facebook, but the recent badges aren't
What is meta?
- Any Stack Exchange user can ask a question
- The community provides support, votes on ideas, and reports bugs
- Your voice helps shape the way Stack Exchange operates
All user settings are inheritted from Stack Overflow. Your accounts aren't distinct.
Badges, being per-user, are also not distinct between the sites.
This is very much status-bydesign. Facebook.StackOverflow is a view onto Stack Overflow, not a truly separate site like an SE 2.0 is.