View the course grade override log in Gradebook
From EdTech Help
Go to Gradebook
Select Gradebook from the Tool Menu in your site.
In the Course Grade column, select the down arrow within the cell for the student's grade and choose Course Grade Override Log
The log will display
The Course Grade Override Log will display the date and time when the grade was overridden, as well as the change in grade and the username of the user that made the change.