Accumulative scale grades are showing as numbers instead of letters. E.g. for  a grade only workshop it shows (what it should show is displayed in brackets below):

Accumulative:
aspect 1: Grade - 5/399 (should be A-/A)
Comment:: feedback for student

aspect 1: Grade - 3/-399 (should be B/A)
Comment:: A minus is the opposite of a plus. 

Note: every aspect can be a different type (point, scale or none), so this needs to be checked for each aspect individually within the one workshop.