That is an old bug, already there in previous versions. I have filed it several times, perhaps you could do the same?
If you need a long message, you'll have to create text captions for Success/Failure and show them based on a conditional action when entering the score slide. Check the value of the system variable cpQuizInfoPassFail.
Since the Review area you are talking about has this bug only on the score slide, I mostly create my own score slide including the Review feedbacks that I'll show based on a conditional action (on entering the slide) that checks the value of the quizzing system variable cpQuizInfoPassFail.
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