Prevent calibre from setting Author from filename

Hi all

First off, I already have the option "Read metadata from file contents rather than file name" checked in Preferences > Adding Books.

But if the book filename fits the format "YYYYYY - ZZZ", the calibre adds the book with "ZZZ" as the author.

The book in question is a magazine epub and does not have an author in the metadata. It does have a publisher name, and calibre picks that up correctly along with the other metadata in the book file.

Any help with this will be much appreciated.