So, In this case the Secretary, put's calender items in the agenda on the mail account of the manager.. I think. So this problem is not related to the exhange server, but to the local outlook account.

I will put a screen shot in my next post on how to solve it!


Over here (unfortantly It's a dutch screenshot I didn't have an english outlook here)

You see Agenda (what ofc stands for agenda/calender) and undeneath that there is StandaartHerrinering. That means Default reminder.
If you turn this of, It SHOULD be fixed. I think this stands for the Local ootlook, so the secretary should still get the alarms.

Hope this helps! (btw.. This menu is in extra > optionts