An odd bug has developed this morning. At the moment, api.stackoverflow.com/1.0/questions is returning a question of the format...

    ... },
    {
      "tags": [
        "jsf-2.0"
      ],
      "answer_count": 1,
      "favorite_count": 0,
      "question_timeline_url": "/questions/3907189/timeline",
      "question_comments_url": "/questions/3907189/comments",
      "question_answers_url": "/questions/3907189/answers",
      "question_id": 3907189,
      "owner": {
        "user_id": 463053,
        "user_type": "registered",
        "reputation": 6,
        "email_hash": "74a43b5cb5829f78b4a4be155c8d702c"
      },
      "creation_date": 1286807749,
      "last_edit_date": 1286810790,
      "last_activity_date": 1286811106,
      "up_vote_count": 0,
      "down_vote_count": 0,
      "view_count": 4,
      "score": 0,
      "community_owned": false,
      "title": "jsf 2 project structure"
    },
    { ...

Note that the owner sub-object has no display_name key (display_name is non-optional according to the documentation). The single question route, http://api.stackoverflow.com/1.0/questions/3907189, returns the display_name as "user463053".

This has broken Six to Eight, as the response decoder now fails with a missing mandatory key error.