Strange calendar invite problem

[Jeff]

Recently, I ran into a very strange outlook calendar invite issue. What
happen is we have a recurring meeting event in our calendar. The meeting
organizer will send out updates if the meeting time is change or canceled for
any particular week. Last week, when meeting organizer send out a cancel
update to all the attendee, it goes out to all attendees. But when one of the
attendee click on remove form calendar, it sends out another update to all
the attendees. Any attendees who click on accept, the event gets update on
their calendar and the organizer changes to that attendee.
This happens twice for the past month. Both incidents are coming from the
same attendee. He said for sure the only thing he did is to click on accept.
The only way I know can duplicate the invite is to retype it. But it is
almost impossible for that attendee to retype the all thing and send out the
invite. I just cannot duplicate this myself. And I check the outlook setup on
that particular attendee and I cannot find anything unusual.
Any suggestion is highly appreciated.