sony v1u editing render in Final cut pro

I shot three tests with my new Sony 24p camera. All three in 24p mode. In one of them, i had to render all the footage in FCP but not in the other two. The settings were basically the same. i think the shutter speed may have been on or something, but i can't understand why i had to render some of the footage and not all of it.

http://www.interkosmosmovie.com