When reminders are configured to be sent ‘x’ hours prior to a specific set date, they will dispatch two emails. The number of emails escalates with each additional date set. For instance, if a task has both a start and end date, three email reminders will be dispatched. If a task has a start date, end date, and a due date, then four email reminders will be dispatched.
Email is set up using Exchange Online over port 587.
Running the command line test email function sends one email successfully.