Odd Exported file Behavior

I edit a weekly broadcast which requires be to overlay and crop a black video file with captions. I then export the broadcast as a ProRes 422 file to retain the Line 21 captioning data. Up until now I have been able to then open that file in quicktime and visually see the line 21 data at the top but now i see nothing. If I open it in Mpeg Streamclip I do see it so I know the information is in the file but I am just curious what is going on. The Movie Inspector in Quicktime says that it is 720x486 as it should be but then it is followed by a (640x480) which I believe must be the culprit. Any thoughts on why it would be doing this? How to fix in quicktime?

As a follow up I have not been able to figure out what is going on but can confirm that Quicktime is hiding the "gutter" of the video file from view. I tried a variety of exports to see if I could change this but was unable to. Not sure if it is related to a recent Pro Video Formats update or something else. At this point I'm just going to live with it an check files via alternate methods (Telestream Switch).

See if this article helps. discussions.apple.com/thread/3822173?start=0&tstart=0

Thank you for the article, I actually already ruled out the actual/current size. I also spoke too soon in believing that since I could see the line 21 data in the gutter in Switch it was working fine. After some more testing it was there but must not be in the correct positioning to translate for CC correctly. I cannot figure out what is going on. I can even create a new library, new project set to auto match to first clip, drop in the CC Clip(ProRes 422 w/ captioning confirmed working), export ProRes 422 and it is no longer working. A task that has worked for years in both FCP7 and X. So my work around at the moment is to take exported file and do the same in Premier Pro which works fine.