Custom resource alert has duplicate learning assignment rows if assignment status previously changed

Summary:

We have a custom learning resource alert sent to managers once a month that notifies them about overdue learning for their team. It uses the Group By function and in the message body table it should include one line per overdue learning assignment (up to 1 year overdue). But some managers are seeing duplicate rows, eg 2 or 3 rows per learning assignment for some team members with the same due date, even though the user has only ever been enrolled in one learning assignment for the indicated course.

We configured the alert using Oracle's 'Understanding Alerts in Oracle Fusion Learning Cloud' guide found on this Knowledge Base article: