For an already graded quiz, where 22 students took the quiz and earned points, I edited it and changed it to Practice Quiz and saved. I then immediately went back and switched it back to Graded Quiz and saved. Now in the grade center only 9 of the 22 grades are appearing. The rest are given zero. Why does this occur??
I do have an export backup of the grades, so I'm not worrying about losing grades. But I want to know why this happened in the first place. Help!