In a Grade book with a Points grading system, the Final Calculated Grade is 0/0.
To fix that,
- Go to Grades and click the blue “Settings” link near the top right of the page.
- Click “Calculation Options.”
- Scroll to the bottom of the Calculation Options page and check the box to “Automatically keep final grades updated.“
- Click “Save,” then “Close.”
This rare glitch showed up in December of 2018.