Note: This issue is not strictly related to the StudioUI, but the customer experienced this problem during work on own LandingPage Blocks.

Steps to reproduce
1) Create the new block
2) Inject @translator.default to the Block class
3) Add translations for the keys used as blocks names (French and English)
4) Set your admin SiteAccess language configuration like: [eng-GB, fre-FR]
5) Configure browser languages preference, for e.g. fr_FR = 1; en_US = 0.9;
6) Clear cache & login to the PlatformUI. Go to page.

Expected result
Blocks should have names in French.

Current result
Blocks names are displayed in English.

More information
You can skip steps from 1 to 3 and use the code attached to this ticket.