Updated recurring appointment loss when accepted from delegate

[Klaus]

We are using MXS 2002 SP3+RollUp Fixes and Outlook XP SP2
+ January Update (OLK1006a)
User1 delegetes his calender to user2, user2 creates a
recurring appointment and invites user1. User1 and user2
get the appointment invitation for user1. User1 or user2
can accept the appointment. All is OK so far. If user2
updates a single appointment (not the whole series), both
user1 and user2 get an invitation the updated appointment
for user1. When User1 accepts the appointment first,
user2 does not see that user1 accepted the appointment
already. If user2 deletes the invitation, the single
appointment disappears from the user1 calender.

I can reproduce this behavior on an other MXS/Outlook
environment

Any Ideas?

Klaus