A few minutes ago, I resoldered an electrolytic capacitor in my downstairs computer, on an NVidia 6200A-LE. Anything graphic intense and the computer would show nothing but colored lines across the screen. I previously replaced the caps because they were blown and leaky. One of soldering joints wasn't the greatest and it became evident. So I went in the garage and fixed the cold solder. Good as new.
On a capacitor of that type, me personally, I wouldn't worry about it. If it fell off lol and the card is still working well (not under warranty too), it's cool. They build the cards with overhead, meaning that if one capacitor fails, there's good chances that the circuitry is able to continue as it should.
If it's under warranty, have them RMA it for a new one or repair.