For those that are looking at this in the future, we found several issues as to why we were not seeing reminder notifications firing.  Thanks to @sbritt  and @Willem for pointing out a couple of the reasons.

1) Interval field must have a value.  We only wanted the reminder to fire one time, so we left Interval blank, but it seems it requires a value.

2) "HR Daily Job" must run as it is what triggers the reminder notifications.

3) The notification named "Reminder notification" must be active as this is used to trigger the reminder.  We had deactivated it sometime back when it was not being used.