#865 Appointment sync errors for unlikely reason

[Milan Brabec]

Hi, this happens to me last couple of days every time I try to sync in version 4.1.12:

2021-09-09 10:20:50 | Information | Syncing appointments...
2021-09-09 10:20:54 | Warning | Outlook exception, please assure that Outlook is running and not closed when syncing: Zadané koncové datum předchází počátečnímu datu.
   at Microsoft.Office.Interop.Outlook.RecurrencePattern.set_PatternEndDate(DateTime PatternEndDate)
   at GoContactSyncMod.AppointmentSync.UpdateRecurrence(Event master, AppointmentItem slave) in .\AppointmentSync.cs:line 1458
   at GoContactSyncMod.AppointmentSync.UpdateAppointment(Event master, AppointmentItem slave) in .\AppointmentSync.cs:line 623
   at GoContactSyncMod.Synchronizer.UpdateAppointment(Event& master, AppointmentItem& slave, List`1 googleAppointmentExceptions) in .\Synchronizer.cs:line 3036
   at GoContactSyncMod.AppointmentsMatcher.SyncAppointmentNoOutlook(AppointmentMatch match, Synchronizer sync) in .\AppointmentsMatcher.cs:line 412
   at GoContactSyncMod.AppointmentsMatcher.SyncAppointment(AppointmentMatch match, Synchronizer sync) in .\AppointmentsMatcher.cs:line 682
   at GoContactSyncMod.AppointmentsMatcher.SyncAppointments(Synchronizer sync) in .\AppointmentsMatcher.cs:line 256
   at GoContactSyncMod.Synchronizer.Sync() in .\Synchronizer.cs:line 2467
   at GoContactSyncMod.SettingsForm.<Sync_ThreadStarter>d__90.MoveNext() in .\SettingsForm.cs:line 878

The inserted line in Czech says: "The specified end date precedes the start date."
Unfortunately, this stops the sync and gives me no info about which appointment record causes this error. Outlook is running of course, as contacts has been already sync successfully. And obviously, no appointment can have end date before start daty, not in Google, even not in Outlook.
Any idea, what could be wrong?
Thanks.