[Ron Moore]

I seem to have found the problem. I am using 2 RME Fireface audio interfaces and when I select them both as an aggregate device (I created) in the audio video settings it causes audio tracks that are synched to video tracks to move in and out of sync and the video to be pause at the beginning and be jerky. If I just select one RME Fireface 800 in the audio settings everything seems fine.

I have never had this problem with Logic so it took a considerable amount of time to troubleshoot. I only found the problem after editing the same footage on my laptop with no problems.

Thanks Paul for your suggestion. Maybe this will help someone else in the future.