Mac Pro 2.66 Quad
ProRes LT timeline
Fully rendered timeline yet there persists a picture jump the first frame of a fade out to black. I've tried keyframing an opacity fade, a crossfade to black, a slug on top of the video track fading in to black... to no avail.
Those were some good troubleshooting tips but nothing changed. Without the fade there's no jump. There were no rogue motion keyframes. When I moved the fade around (location and duration) some weird things happened. The video would flash back to a moment earlier in the clip for a few frames and then return. I've seen that before a couple of times in FCP history and chalk it off to some reference hiccup. Anyways... the work-around I used was to export the timeline without the problem end fade and bring that self-contained mov back into FCP and then add the end fade. Success.
Side note: My source footage was a 720p download from Youtube (h264) transcoded to Prores in MpegStreamclip. Maybe this helps explain the jumpy fade.