Over the last 10 days it seems 2 of the 4 charger cords I had failed. Two came with the devices and two came with 3rd party wall / car charger combo units. It looks like the the that failed were the original Apple cords. The chargers still work but the cords themselves seemed to have failed. They are always plugged an unplugged using the connector and not yanking on the cord itself. Anyone else ran into something similar?