By default, Appointment Reminder does not sync All Day events from Google Calendar. If you want to enable All Day events then you will need to enable this for each Google Calendar.
Go to Calendar > Edit Calendars and click edit on the Google Calendar you want to edit.
Scroll down to the Google Calendar options and change “Sync All Day Events” to true.
Once done you click save. Once a sync is complete you should no long see these inside your Appointment Reminder calendar.