Currently Being ModeratedFeb 17, 2012 10:58 PM (in response to spencer1812)
From this thread at macrumors.com:
"If you merge the duplicates, it will sync back to iCloud properly.
From your iCloud connected Mac: Address Book > Card > Look for Duplicates. Then it will ask if you want to merge them."
I just spent most of the evening struggling with this issue, and was making plans to call AppleCare tomorrow or even visit the Genius Bar at my local Apple Store. After I found the above quote, I fixed 400+ duplicates in under a minute.