User interface language switch does not happens

Although PortableApps platform uses Italian localization (and the checkbox "use for all application" is ticked), I cannot switch LibreOffice user interface to Italian when launched from PortableApps menu. The user interface remains in English(US) whatever language I choose.

The switch correctly happens if I start the launcher directly from file system.

I have already tried last Fresh and Still versions with base languages, and Fresh version with all languages.