1. Go to platformUI;
2. Create Folder on Home in eng-GB;
3. On Folder, click on Translations on rightside menu;
4. Click on +New Translation from the small pop-up windows;
5. Click on nno-NO, click on Confirm (leave the checkbox checked or unchecked, it's indifferent);
6. Rename Folder in this translation to "Folder NO"; Click Publish;
You should be redirected to Folder view.
Notice the dropdown for translation is in nno-NO, but the Content fields underneath are showing the eng-GB version.
7. Check the dropdown that shows nno-NO. There is a small expandable arrow that means there are more than one choice on the dropdown. Click it and click eng-GB. After having chosen eng-GB, only eng-GB version shows now, you can no longer change back to the translation you just created (if it was created at all).
Not sure if this behaviour is specific to folder/any of its field types, or not. Tried the same on an article with different result, which I reported on
Tested on both Firefox 36 and 39.