Unable to pass when retaking a quiz because passing score becomes impossible
I have run into some glitchy quiz behavior in one of my .story files. Every time someone retakes a quiz (based on a Question Bank draw), the points the learner has to earn to pass the quiz (PassPoints) are increasing. So if they fail the quiz and they had to reach 20 points to pass, when they click "Retake Quiz" the Results.PassPoints variable is inexplicably increasing by the amount they need to pass. This makes it impossible to pass the quiz and makes the learner think their score is getting worse each time they retake the quiz.
E.g. The first time they take the quiz, if they get 10 points and the passing score is 20, when they retake the quiz and do get 20 points, even though they should have passed this time, they fail the quiz because the pass points have been increased to 40. Then if they retake again, the passing score goes up to 60, 80, 100, etc...
Also, on the first time the quiz is taken, if the user skips the first question and only answers the last question, they pass the quiz, and the score says only 10 points were required!
You can see this in action here and in the attached story file (which is a very much stripped down version of the actual course):
It gets more bizarre though. If I remove a slide from an unrelated Question Bank (titled "Copy of Dressing Change") that isn't part of this quiz at all, the scoring starts working correctly. Has anyone encountered this before? I'm thinking the slide is corrupt in some way, but I can't tell what is going on or why it would behave this way.