This would indicate that either the leaving date of the pupil or the exclusion date is not correct. To check these dates please go to Admin > Students > Search Not on Roll - search the student name in the student dropdown and choose, click to view profile.
Once on the profile to check the exclusion information please go to the conduct tab and in the bottom left select exclusions - ensure the exclusion dates are correct for the student, if not, click edit here and amend the data.
If this data is correct you can check the leaving date of the student by going to the extended tab, scrolling down under school information and check the leaving date here. If you amend this please ensure to save at the bottom.