The function with changing the movie file path from one disk to another is working OK, and the "Media Label" is changed too, but "Media Label" is changed for all movies in the hole database.
It should only be changed for those movie files with the old path.
It's luck, that you have an advanced filter, where you can choose "Movie file 1" begins with........ and change "Media Label" back on all the movies on the disks, that have been affected with this error.
I would prefer, that it's only the movies from old path, because if you move movies from several places and change one by one (different old path), you would have problems seeking for the rest of the movies, if you change Media Label at all the movies at once.
But there must be a bug somewhere if movies from other harddisks and paths are changed in this process.