Two users on the Xbox Support forum have reported that their Xbox One had an amber light on the power brick and, when they plugged it into a different outlet, the console began smoking from the top. Sending the console back to Microsoft will get you a replacement console. One user said that the amber light appeared and, when they reset the power supply, the console made a buzzing sound and then began to smoke.
No word if its a refurbished or a brand new console but, if the console is smoking, the best thing to do is to carefully unplug it as it could lead to a far worse problem. Better safe than sorry, right?