Gradebook Classic / course grade display

Gradebook classic course grade issue:

Course grade display can show incorrect grade for student.

To replicate:

Create a site with Gradebook classic and add student(s)

You can leave the course grade options default where 90 should be a A-

Add a gradebook item worth 100 points

Grade student on that item at 90 points

Save

View the course grade tab.

The score will show as 90, but will display a B instead of A-