I am giving timed multiple choice questions on Canvas quizzes.  I often see student submissions marked "late" (their cells are highlighted in blue).  How is it even possible to have a late submission on a Canvas quiz?  Doesn't the system  automatically submit a student's quiz as soon as the time is up?  How can students continue to be taking the quiz after the "due date" has past?

The reason I ask is that I have the quiz due at a certain time and then usually 1 min later, I have the system release the correct answers.  If students are able to take the quiz even AFTER the set deadline, then this means they will have access to the key.  Thanks for your feedback.