I started to import a movie folder by just importing a single folder. The names of the imported movies weren't the wanted ones because of incorrect folder names. So I then renamed all folders and deleted all the files from the Media Library. After that I imported the folder again, but the names didn't change.
I then configured auto-import of the movie folder, but the name of the movies didn't change this time either. I have also tried to clear the whole Media Libray and then imported the folder again, without any change. The wrong/previous names (and tags) are still there!