I really don't have a clue. But please, if it stays on all the time, talk to me about servicing your ST. I put Safety First! That is why I designed the ST in the first place!
I only know of one case where the ST stayed on... he sent it back along with the 901 adapter he was using. Come to find out, it was the adapter shorting out. We tried a different adapter and it worked out fine. Other than that, I suppose maybe putting the batts in the wrong way could do something to the circuitry, or
vaping on it to the point where it got so hot from the atty that it could have caused something. Other than that, the circuitry will shut down on it's own for a while in the case that the circuitry overheats.
Also, if the 510 connector is silver in color, you might want to check the little round silicone separator inside at the base of the threads. Sometimes, if a user tightens the atty way too hard, this may come out or loose. That's just from really over-tightening the atty. If this is the case, try to push it back in. The new gold connectors that we use don't have this problem at all. This is why we tell people not to do this with their atties, as this can happen on any
mod with the connector.
I've never read that the ST had caused a burn in someone's clothing... if that had happen, I hope the person would email me to let me know. The ST, just like any other
mod, should have the atty taken off when not in use. Even one's with On-Off switches, since that's just another electrical part ready for failure. Remember, mods are just battery connectors, and a lot of times, on any mod, what is put on top can make things go wrong.
And PLEASE... if anyone has some type of problem with their ST, please notify me, whether you bought it from Vapor Moon or in the Classifieds. I'm right here to help with any problems, and sure to find some type of correction.