After switching language, "sign out" dialog button doesn't appear to work

After changing the app language in the Briar settings screen, a dialog is shown prompting the user to sign out. On the Samsung Galaxy Ace 2 (Android 4.1.2) the "sign out" button dismisses the dialog and brings the contact list to the foreground. The UI remains visible and usable for about 15 seconds and then disappears when sign out completes.

Ideally the UI should be hidden immediately and if the app's relaunched it should show the "signing out" fragment, as happens when the "sign out" menu option is used.