We have not heard back from you. If you are still having trouble, consider the following:
If you have not already done so, restart Mac and test again.
If the problem continues after restart and after using CMCSK's excellent QT suggestion, test iMovie recording.
If you want or need more suggestions for sync problems, see:
(You show OS 10.8.2; its Combo update is at http://support.apple.com/kb/DL1581)