A copy and paste issue started with one of the patches to FTM 2012. It's just still around in FTM 2014 apparently. On my end I can easily replicate it. It happens whenever you copy something, then open up the source citation dialog, then paste. It always pastes the tooltip text (what you read when you moues over the citation). To get around the bug, open the source citation dialog first, then copy, then paste.