Wonder if the timeout period itself has a timeout. For example if I hold the button down it may shutdown after 10sec but turn back on after another 10sec. The staggered discharge could accumulate enough heat to burn. I'll have to test this out.
I can confirm that both our VV's have a working 10second shut off circuit. It deactivates after holding the fire button down for 10 seconds. Keeping it held down doesn't reactivate the device. I wonder if it somehow got turned on and off continuously in the handbag or something else happened. I suppose a collapsible battery coil or something similar could have helped break the circuit when it got to a certain temp. Maybe it's time to move back to a device that doesn't have a built in battery. :-/