Yeah there are just a lot of titles with weird rights situations that no one cares about resolving. Maybe you lost clearance on a song in the movie, or one of the actors has a clause in their contract, or some company bought the distribution rights for a certain territory and then went out of business.

Lots of situations where resolving the rights issues is going to cost more than you expect the movie to bring in, especially once you start talking about splitting the revenue with online storefronts.