Outlook.com - eM Client reminders with wrong alarm time

I have eM Client Version 9.0.1708 running.
I have synced it to my Outlook.com account (SMTP, IMAP, AirSync).
Currently it seems as the alarm in calendar events is not working correctly.
For example: I create a new calendar event and set the reminder to 1 hour before the event starts.
If I check the item online on outlook.com the reminder states: 0 minutes ==> alarm on event start.

Why is this happening? Does this have something to do with the ICAL-format?

With this problem the calendar is not working for me.