I have a student who is getting notifications sent to her email for assignments she hasn't completed. They look like this:
That particular notification is for an assignment that has been graded. I have no way of telling, but have you verified that the student did not submit the particular assignment that Canvas notified the student had been graded?
If the student did not submit that particular assignment, or if that assignment has not been graded by you, then this is a bug and you should contact Canvas Support. Learn more at How do I get help with Canvas as an instructor?
Keep in mind that Canvas considers your entry of a zero, to also be grading. I routinely mark zero for no-submission, and Canvas sends my students a grading notification for this.
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