Bill reminder has wrong amount

I have a bill reminder that is showing the wrong amount. I have the reminder set up to estimate the bill by using the last 3 payments. Those payments are $73.06, $71.58, and 81.97. The reminder shows the next payment to be $1740.36.

If I edit the reminder and change the number of previous payments to 4 and then back to 3, that panel then shows the correct estimate of $75.53, but when I click done, it still shows the estimated payment to be $1740.36 on the list of all my bill reminders, Just for kicks, I changed the number of previous payments to 1 and on that panel it shows the correct estimate of $73.06, but when I click done, it shows the estimated payment to be $5005.20 on the list of all my reminders. I don't know where it is getting that payment of $5005,20.

Any ideas on what is causing this bill reminder to be so wrong? Thanks