Cannot Override Quiz Grade, 2.2.4

Cannot Override Quiz Grade, 2.2.4

by Kimberly Noseworthy -
Number of replies: 0

I've tried everything I can think of to override a quiz grade, all with no success.  When I enter the grade in the gradebook I'm getting the following error message:

Error Click this box to remove it
TO BE LOCALISED: Failure to update final grade!
 
This only happening on two students.  One did exceed the time limit on the quiz, the other did not.  I've cleared the attempt for one of them, no change. 
 

I'm at a loss.  Any ideas?