Currently Must Do courses with assessments move to history as soon as the leaner has completed the content and attempted the assessment irrespective of the assessment result. If the learner has more than one attempt for the assessment it will make it easier for them to find the course again if it remains in the Must Do section until they have successfully complete the assessment or reach the max. number of attempts as if they do not retake the assessment immediately when they log onto the platform it seems like they have completed the course.