One other thing to consider, @darwinjhargrave , is that you might actually have duplicate assignments. If so, you will need to unpublish or delete any dupes before students try to submit to them. You can identify dupes from the Assignments Index page.
I suspect, however, that Kona is correct. Many teachers will add calendar events that remind students of coming assignments, and phases of an assignment. Most commonly this is with discussion that might use two due dates - one date for the original reply, and another one for the classmate replies. If you click on the links in the course Summary, Canvas will take you to that entry - either an actual assignment or a calendar event to help you troubleshoot.
Kelley
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