One problem related to brake disc pads has been reported for the 2013 Nissan Leaf. The most recently reported issues are listed below.
I was driving the car on a one-way street at around 25-30 mph and needed to apply the brakes to stop quickly. I hit the brakes with all the force I could with my leg---the brakes did not engage and the car did not stop in time. It seemed like some kind of weird glitch because I understand that the car has electric support for the brakes. At other times the brakes didn't respond in the correct time. Note I had the brakes inspected several times by a puente hills Nissan and the brake pads were fine. There was also a strange clicking noise coming from the brakes when they disengaged. It seems to be some kind of time delay in the software. I also read that since the car has regenerate braking it's like the car gets confused when it supposed to apply the brakes and not slow down from the engine. I had trouble braking other times when I wore light shoes or sandals.