If a Student logs in, goes to their Progress Tab and can see the Courses, they see a button called Grade Detail but the Grade is displaying as -- --.
The likely cause of this is because by default, the Progress Tab will always default to Hide. Even after the Student changes the settings, once they navigate away from the page or log out and back in, they will always land on Hide.
To display the Cumulative Grades, navigate to:
The Progress Tab > Click Show
The Grade Detail (Cumulative Grade) now displays to the Student as shown: