So this has happened in two different types of assignments. One is the quiz feature I used an assignment but isn't a quiz; I use it for self grading purposes all of my assignments and counted was homework/classwork. The other was an assignment with an external tool for the assignment.
I would make a duplicate for review if it was easy to duplicate assignments without have to actually create it each time. Our district doesn't want our assignments with end dates on it.
I really think that after the due date if there was a feature that would automatically make the assignment as view only after the due date. Also, I wish that Canvas would allow students on accomodations to get automatic extra days, that can be set at the start of the year.
I use Derivita for my assignments in math, which is an external tool. The program's creator is a co-founder of Canvas and some of the features Derivita has would be so helpful in Canvas.
Especially as a math teacher the options Derivita has is FAR better than Canvas.