Reoccurring calendar entries for Reoccurring Meetings

Hi all

I am currently looking at a clients calendar that has a strange error.

The user has a reoccurring calendar entry for ever day that is a meeting entry, she is going on leave next week and as such deleted all of next week entries and sent out notification, which was fine. Now for the rest of the year instead of there being the 1 reoccurring calendar entry there are now 6 entries reoccurring , I know i can just delete all entries and start again but i would love to know the cause in case it happens again.

We are currently running Notes 6.5.6 client and we have cluster servers setup for the mail server that this user is connected to ( cluster version also bugged).

thank you to anybody in advance that replys to this thread.