This is happening to me all the time. I recently upgraded from my 8820 (which synced perfectly) to a 9700. After my first few syncs I noticed that my contacts were duplicated, and the ones that weren't all the info within the contact was duplicated. Fore example it would go from having one email or home number to having as many as 10 home numbers all identical.
I'm using BB Desktop Manager and syncing to iCal and Address Book on my macbook, and as I said above it never happened with my 8820. I find this funny because the 8820 is so outdated that I thought the 9700 wouldn't have a problem at all. I have had to go through my entire address book (hundreds of contacts) and try to manually correct all the duplicates. I'm wondering if switching to Missing Sync would enable a more seamless sync, but either way something is going to have to change.
I know this didn't in any way solve your problem, but I too am looking for a solution if you or anyone else has any ideas.
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