Team Calendars Reminders are returning multiple instances of a single event

[Buc-ee_s IT]

One of our space admins set up 'Reminders' on his calendars.   He recently reported that he's getting multiple instances of a single event in the 'Team Calendar Reminders'. 

This is not for all of the events, but specific ones.   He's even gone so far as to completely delete the events from the calendar, but they continue to come in.  

Example Reminder Email:  

In 1 Day

• FI Report Submission 
• FI Report Due
• FI Report Due
• FI Report Due
• FI Report Due
• FI Report Due 

I've looked through all of the settings, and I cannot find a way to correct this, nor can I reproduce it on any other calendar.   

Note:  The event in question (FI Report Due) doesn't even show up on the actual calendar anymore.