problem with mannaging meetings when Application events are

Hi,

I'm developing Addin using VB.Net with VSTO to OL2007.
During my development, I came to the following strange symptom:

If I'm using event handler for any of the Application Item events (ItemSend, AdvanceSearchCompleted, etc.), I cannot update a meeting by shrinking\expanding it on the calendar more than one time. After the first time (in which OL send the updated meeting), the second change is saved only locally, and OL is not sending the updated meeting.
It happens even if I have no code in the event handler.

Another annoying issue, under the same conditions - handling an Application Event:
When I'm updating recipients of the meeting, by deleting one recipient and adding another, only the update is being sent from OL. No cancellation! Removing the event handler makes the cancellation to be sent.

I've disabled all addins on my machine, made a tiny addin, that has only *one empty event handler* for the Application Object, and all the symptoms there.

Have anyone bumpped into something like this?
Any idea?

Thanks!
Moshe