I have used "SpeedGrader" to grade quizzes. I have clicked the bottom "update" button on each quiz as I finish grading it to update the scores.
And still, despite each quiz having a non-zero score associated with it, the gradebook shows all zeroes.
See attached screenshot.
Circled on the left: the grade for this particular student's quiz submission, for which I have already clicked "update" at the bottom.
Circled on the right: 0/5, which is what the gradebook continues to reflect.
Is this really the state of Canvas?