That happens from time to time - look in the photo taken only seconds before it here:
Joseffa Meir approaches the crux moves of the third pitch (10b) of 'The Naked Edge' in Eldo. Photo by Tony Bubb, 5/07. Submitted By: Tony B on Aug 10, 2007
I made up some quickdraws with these small biners and took a fall on one that completely came uncliped and sent me to my next draw. I was lucky I was way off the deck. Don't trust mini-biners for draws!