I have had my sigelei 20w going on the 2nd day now. On more than a couple of occasions I will press the fire button to have a vape and the device will completely shut off and will not come back on until I take the battery out and turn it back on. It has happened while using a sony vtc4 and an efest battery, both are 18650. For the most part it has worked great but I am worried this could lead to more problems down the road.