Exchange 2010 Meeting Request not marked as tentative - sometimes

Hi

I have a user (1 out of 7000) who complains that sometimes meeting requests are not marked as tetative in his calendar.

Outlook 2007 and Exchange 2010.

As I understand, all the stuff about calendar sniffer is history in Exchange 2010 due to the Calendar Attendant - right?

So when the calendar attendant is set correct and the automateprocessing is correct - do you have ANY suggestions where to look?

BR
Steen