If a lesson is shared between multiple courses, when a user completes that lesson in one course, it should be marked as complete in the other courses as well. Since the lesson is shared and the content is the same, users shouldn't need to redo the lesson, and the completion should be tracked and updated across any instance of that lesson's use.
I completely agree, Our largest client is looking for this and we can't tell them no.
I completely agree with Nikki on this suggestion! We even have a great use case that I would be happy to show the product team essentially creating a curriculum within curriculum effect and the only limitation is that shared lessons do not mark credit for both.