Parents and students see activities as Overdue in the activity page but not on the course page. This is confusing as it is showing different information depending on the view within Schoology.
The currently intended behavior is that the Overdue area appears on the homepage only, not at the course-level. Another way students could see if they have something overdue right now would be to Grades, and view when an assignment is due. If they have submitted something, it will show an icon next to the grade placeholder.