- Browse to "Site administration" > "Courses" > "Backups" > "General import defaults"
- Disable backup_import_questionbank
- Create a course and add a quiz to it
- Navigate to the course you containing the quiz you just made
- Attempt to duplicate the quiz (edit menu > Duplicate)
The duplication fails, with no indication why. The user should at least be notified somehow of what they need to do in order to get the quiz to duplicate.