“Father, your son has burned your roasted cup of tea, despite all its protection.”
Q: Let me know, mother of the idiot, how did this happen?
WOW: easy and simple: came from the store, threw a package of products on the table and went to play. Next - a coincidence: the package fixed the switch in the position "incl", the water in the cup was, but the lid was not closed. In addition, there was little water. Therefore, the lower thermostat was fixed and could not work, the upper did not have enough temperature, and the water at the time of switching, was.
As a result, your cupcake turned on and did not turn off.
In short, the fool hacked your defense against the fool, not noticing it :-)