I’ve discovered an issue (with the help of a very upset student) regarding edited discussion posts in Canvas. Apparently, there are some students who post generic responses on the discussion board (or just a period even), and then come back to the discussion board after the deadline to revise it. This allows them to still get full credit while technically having submitted the assignment after the deadline since the instructor isn't made aware of the situation. While grading (especially in the speed grader), the instructor isn’t notified that the post was edited after the deadline. Additionally, there is no way to see the original post before the edit.
I've attached a document with screenshots that shows the issue.