We turned it on for one school which is not using Canvas this year. So, it seems that if a student or teacher ever had a course at that school, they are seeing the new dashboard. Than means if they moved on to Jr. High or High School, it was still showing that dashboard. I'm not sure if there is a way to prevent that other than deleting old courses?
Always great to hear from you! This is a known issue. Our engineers are working on a solution that will handle this on the backend and not require you to delete courses from previous years. We'll be sure to update here once that adjustment is in place.