"Current grade in Assignment" does not show scale values

To reproduce....

1. Create an assignment
2. Grade using a scale. The "excellent/very poor" scale will do
3. Select blind marking and marking workflow
4. Either log in as a student or edit on behalf of and upload a PDF submission
5. Click Grade for that student
6. Give them a grade from the scale (e.g. Excellent)
7. Save the page 

You will now see that it shows "current grade in Assignment" on the right hand side. However, it shows a numeric value (presumably the internal representation) not the scale value.