I suggest you play the original DVD, or at least read the "Special Feature" notes, maybe you find the answer there. I see many versions of First Blood, you need to identify your version.
If not Wide Screen Vs full Screen issues that is easily determined with play playback button in DVD Shrink, the most common answer might be slighly different version i.e. not-rated Vs rated, some extra long scenes, etc. You do not see this is the size of the VOB, it is controlled by the IFO, and normally you set it up from the menues, either Main or Bonus.
Try loading this movie in free program VobBlanker, and see if it finds "reuse cells" chain for the main movie title.