Editor username and link aren't displayed when trying to edit a page with another user if the page language is not English

Steps to reproduce:

1. Login with an Admin user (U1)
2. Go to Global Administration: Localization and set:
   • MULTILINGUAL: Yes
   • SUPPORTED LANGUAGES: English, French, German, Italian
3. Create a new page (P1) and add translations for all supported languages
4. Create another user (U2)
5. Login with U2 in another browser
6. Edit P1's French translation with U1
7. Try to edit P1's French translation with U2
8. Repeat steps 6 and 7 for all supported languages

Expected results:
The name and a link to U1's profile page is displayed on step 7 for all supported languages.

Actual results:
The name and a link to U1's profile page is displayed on step 7 only for English.
For French and German you see the corresponding translation for "Unknown User".
For Italian you see the text "Unknown User".