Adding Back to the future movie 1-3 to the library don't works for German version of movies

[urs45]

I have added the movies Back to the Future (1985), Back to the Future II (1989) and Back to the Future III (1990) to the library.
The relevant entries in the Library Movies Folder have been created, so far so good.
But the newly added movies do not show up in the widget nor the Library recently added items Folder.
As I am using German version of KODI and TMDBHelper the .strm Files have got the german names:
Zurück in die Zukunft (1985), Zurück in die Zukunft II (1989) and Zurück in die Zukunft III (1990) and i guess the german
denomination causes the issue, maybe because of the letter "ü".

My Workaround was to rename the .strm Files to the English titles, after renaming and a library update the movies appear in the Widget and Library Recently added items Folder now.

Anyone has made the same experience and maybe found an other solution to solve the issue?