I don't know for sure what the original problem was, but the most recent issue was a result of implementing [a new badge](http://meta.stackoverflow.com/questions/341214/introducing-the-silver-census-badge) without rebuilding the API. Once the API was pushed to production, the bug was resolved. If it happens again (especially if there's a new badge) please let me (or really any employee) know. We can contact a developer directly.