Collection of local metadata does not work

Why is collections still not working for local metadata?
Everything is set correctly in the NFO. Infuse does not recognize it. Every other app will recognize it.
It only works with online metadata.
But I do not want that. I want to choose my poster, fanart, genre myself.
All other data such as poster, genre, fanart, year, description work locally. why not collection?
Such a small function can’t be that difficult.