When I disconnect the input voltage PIN1 (IN) by removing the USB cable from my device, there is around 24mA of reverse current. This current drain the battery of my device. My input capacitor is 1uF. Notes that this behavior is intermittent, sometime there is no reverse current and sometime 24mA. If I disconnect and reconnect the battery, the reverse current drop to 0mA as expected. How can I avoid this behavior?