pubdate from nomefile

[raffabelli]

In Settings - Adding books
I uncecked the first line, so Calibre should load metadata from nomefile
In regular espression I put

(?P<author>[^_]+) - (?P<title>.+) - (?P<publisher>.+) - (?P<pubdate>.+)
This is the nomefile:
Di Marco, Carlo - La difesa dei diritti fondamentali - Federalismi - mar, 2017.pdf

Well, Calibre take author, title and publisher, but it does NOT load pubdate, I mean this metadata field remain empity in Calibre
I wonder if it is because I am in Italy and windows 7 is with Italiad data format.

BUT
If in Calibre I fill manually the metadata pubdate with mar 2017
Then in Settings, Saving to disk I write
{author_sort}/{title}/{authors} - {title} - {publisher} - {pubdate}
then I save te book to disk, the saved nomefile is:
Di Marco, Carlo - difesa dei diritti fondamentali, La - Federalismi - mar, 2017.pdf

That is in the nomefile of the saved book:
- the title is a bit different from that one in Calibre. Why? As regards some other books I found some mistakes in the saved to disk title.
- pubdata is correct. It means that in Calibre pubdata is not loaded from nomefile but it is saved properly to nomefile. Why it is not loaded?

Both in loaded nomefile and in saved nomefile the date is
- mar, 2017

I attach the original file.