Greetings! I did some research to double-check and on the following guide How do I apply a Late Submission policy in the Gradebook? - it notes that, "to exclude a specific assignment, mark the submission as something other than Late in the Grade Detail Tray." Yet, to fix this, you'll need to adjust it for every assignment submission that was marked late. So for one assignment, you'd need to go through and fix it for each student that was late. For more on this, scroll down on the guide to "View Grade Detail Tray." It shows and explains a bit more about how changing it from "late" to "none."
As for the missing assignments, changing the due date shouldn't remove the assignment from showing up on Grades. I'd try backtracking and try to un-do what you did when you changed the due date. My guess is that you might have accidentally changed something else. Or, you accidentally changed the view of your Grades page somehow. This is kind of hard to trouble-shoot without actually being in your course and seeing what is happening.
Hope some of this helps! Kona
This discussion post is outdated and has been archived. Please use the Community question forums and official documentation for the most current and accurate information.