There is a Catalyst feature that allows students to answer quiz questions and save the answers, without submitting the quiz for grading. This is good and bad. It means that you can finish the quiz questions at different times.
However, it also means that you can complete all the quiz questions without submitting it for grading. To submit the quiz, be sure to select this option at the very bottom of the quiz, once you have completed all the questions.
NOTE: Please check that your quizzes are graded. If not, check that they are submitted. If a quiz id still in the “open” status, it can not be graded. There are several students who have quizzes in the “open” status.