So I recently picked up a Flip Video Ultra HD to test it out. I immediately noticed when trying to dump the video to my MAC that the video was jumpy. And the audio was out of sync. Well as you can imagine, my first thought was to pack it back up and return it. I did some immediate research but found nothing.
Day 2: I found the solution, which I was thinking to begin with but just had no time to test.
Upgrade the Flip Share software to Release 5.0.5 (PC/MAC).
Visit the following link http://www.theflip.com/en-us/App/fvsw/5.x/update/
After installing, it will tell you it is going to update the device software. I am not sure if this includes a firmware update, but will have to test on another mac at a later date so see if the corrections carry forward. You can get instructions on how to check firmware by going here: http://www.theflip.com/en-us/app/fvsw/CheckVersion.aspx
NOTE: The issue I encountered was on a Dual G5 Running Leopard. I have not tried the resolution on this machine. Video seems to be working perfectly on my MBP running Snow Leopard.