Not sure how you were able to put these layers of video inside the sync clip. As Tom said, it is meant for one video and one or more audio clips, not multiple video clips.
But try this:
1) Select the Sync Clip in the browser and try Clip->Open Clip.
2) In the Sync Clip timeline, insert the object in question.
3) Step out of this timeline, and try to playback the Sync Clip in the browser. Does it work as you expect?
4) If the previous steps succeed: select one of the sections in the timeline, and press Shift-F. Drag the selected portion in the browser over that section in the timeline. Choose Replace.
If that part is working as desired, repeat this process for each of the other parts of the clip in the timeline.