Try blowing compressed air into the lock. I would make a fine nozzle using small tubing and work it around the inside of the lock. This will probably not work but I have a compressor so it would be worth trying.
BTW, I have read nearly every article on the internet that deals with these latches and this particular problem and none of them are detailed enough to work from. Photos would be good but the ones I have seen are too dark, too light or out of focus.