Autosave or double clicking save throws the student out of the quiz

If a student clicks on the save button at the same moment of autosave, the student gets the error message of data discrepancy and has to get back in the quiz.
It doesn't happened with the "Next" button.

1. Make sure the autosave on. (For the quiz, it is easier to put it at one minute)
2. Create a quiz with several question.
3. Timer not necessary, but it helps doing the quiz.
4. In layout, make sure that each question is on its own page.
5. Connect as a student and start doing the quiz.
6. Answer the first question and watch the timer
7. Click on the save button as the timer gets to one minute.
8. The student is thrown out of the quiz and get an error message.