There are a lot of older quizzes that went online before games like the Challenge came along. These quizzes weren't written with the current games in mind and don't meet the standards placed on quizzes today. Once the questions are selected for the question pool for each of the various games, it will take a while before they circulate out. Even though a question may have generated a correction note and has been fixed, it will still appear in the games in its original form. Likewise, if the entire quiz was found to have multiple errors, it may have been taken offline by an editor for correction, or it may go offline automatically due to outstanding correction notes, but any questions from that quiz that are still in the pool will continue to circulate for a while. I don't know how often the questions change, so I can't really tell you how long a "bad" question will remain in the question pool.
Never be too open-minded. Your brains could fall out.