When language is switched from Ukrainian language to another, Composed message became blank

Preconditions: set up User1 account
1. Login to Forum
2. Choose Ukrainian language in top menu
3. Go to Messages
4. Click on Compose New message
5. Fill out New message fields
6. Choose another language in Top menu(Eng or Ru)

Actual result: User is redirected to blank Compose message page
Expected result: notification"Are you sure you want to leave this page?"

NOTE: reproduced only when Ukrainian language switch to another language