1. Clicked on a song in the "New translations list".
2. While on the songs page, clicked login.
3. Chose Facebook. Typed login details.
4. Got redirected back to song page. The orange "Login" and "Register" buttons were visible.
5. Clicked on "Login". Got message "Login successful" and under that "You are already logged in".
I know this isn't probably worth reporting since it's not a major bug but still, maybe you can fix it in some future website update.