Here are the following steps on how to reproduce this bug:

1. Once logged in to Confluence 3.5, navigate to Browse -> Confluence Admin -> Languages
2. Change it to either Deutsch (Deutschland) or français (France)
   
3. Go to your own profile via Settings and edit the Language
4. Changing it to either Deutsch (Deutschland), English (United Kingdom), and français (France) will change the language display immediately
5. However, when selecting on *Site Default (Deutsch or français), it will always be displaying in English
   

This problem does not happen in previous versions of Confluence.