There definitely does seem to be something up with the studio information.
It may be something to do with the script.extendedinfo.
I've worked out what happens. If you are in your movies library and you come across a set, it will then add the movie studio for that set (universal for example) on the end of every movie studio for the rest of the movies, until you come across another set. It takes the studio from that set and then adds that on to every movie.
It also adds the set studio onto TV show studios as described before.
The only view it doesn't seem to do this on is right list.
I've attached some screen shots.
It may be something to do with the script.extendedinfo.
I've worked out what happens. If you are in your movies library and you come across a set, it will then add the movie studio for that set (universal for example) on the end of every movie studio for the rest of the movies, until you come across another set. It takes the studio from that set and then adds that on to every movie.
It also adds the set studio onto TV show studios as described before.
The only view it doesn't seem to do this on is right list.
I've attached some screen shots.