The joys of complex rights issues

So I watched the movie Casanova Brown, and noticed two things in the opening credits. First, there was a color screen of the MGM lion, complete with the MGM website URL at the bottom. That's a good indication that MGM got the rights to this film at some point after they sold off their library to Ted Turner in the late 1980s. Then in the actual opening credits of the film was a line saying that this had been produced by "International Pictures". This got me curious.

International Pictures was a minor production company that combined with the American arm of the J. Arthur Rank Organization in a merger with Universal Studios in about 1947. If you've watched any "Universal" picture from the late 1940s or the 1950s, you'll recognize the Universal International logo with the ridiculously long serifs on the T's. And yet, the rights to Casanova Brown apparently did not end up with Universal as part of that merger. (That having been said, a lot of Rank's movies, such as 49th Parallel, did wind up in the hands of MGM after the selling off of the library to Ted Turner.)

A further search at IMDb revealed two things. First, on its original theatrical release, Casanova Brown was distributed by RKO. Second, there were two other production companies listed. One is "Nunnally Johnson Productions", which was presumably a dummy corporation set up for tax purposes since it really only produced this film. (IMDb lists one other film four years later, in conjunction with some other production company.) And then there's the "Christie Corporation", which produced two films in 1944. So I have no idea who kept the distribution rights after the original release.

Of course, back in 1944, there wouldn't have been any broadcasting rights, let alone cable rights.