Hi Chad,
I am sitting in the same boat with you! 😉
Could you find an explanation for the problem? Did you open a Bug report with Apple?
I am also bluring 😉 so at least I have an indication now where the problem is related to…
I am working with FCP 7 (Final cut Studio) and have exactly the same problem. From a certain point FCP is not round triping any more to Motion. It takes the audio and the right file length and opens this then in Motion. But Motion shows only a froozen frame from somewhere in the FCP timeline. The audio en clip length are correct in Motion… but there is no video.
I am looking forward to hearing from you.
Regards,
Mario