Reminder emails going out AFTER appointment is completed, nothing in log.

We blocked out some party dates on August 14th 2016. You can tell which ones as they are called Staff Party. (They didn’t realize I could block the day!). After the party, on the August 21st, reminder emails were sent to the customer email (one of ours) for each “party”. There is no record in the log so it’s incredibly strange. We have no way of checking to see if this is happening with customers or not. Can someone check to see what caused this?