Wrong language is displayed for one user after another changes language

Steps:

Make sure both test users have English saved as their language
Log in with user 1
Go to Settings view and change the language from English to Estonian, save, log out
Log in with user 2 (in the same browser)
Application is in Estonian but should be in English as displayed under user 2 settings
Refresh page, application is still in Estonian
Open application in another browser (or incognito mode) and log in with user 1
Application should be in Estonian but is in English

leelokas / vacation_tracker