I have Outlook 2007 and I'm synching with CompanionLink 4.0 USB to the Android HTC-EVO.

1. I have an appointment that is reoccurring. One instance was changed from Thursday to Friday (the rest are still on Thursday). Once it sync'd to my EVO, DejaOffice showed the Thursday appointment as reoccurring and showed the Friday appointment as a single event, thus duplicating.

2. On a similar, but different note: I have a reoccurring event that I changed the alarm time in my EVO. Once it sync'd it showed the reoccurring appointment without the alarm time changed, and then it showed an new duplicated appointment with the updated alarm time for that single day only.