I had this happen once while reading. I was taking really small chain puffs for I don't know how much time and suddently I got like mega hot hits and juice was literally coming out like hot lava. Removed atty, cleaned, put on, same thing. I could hear the juice sizzle inside the chamber.
In my case, I left the unit rest for an hour (was too lazy to check what was going on with the computer) and after that everything went back to normal. It probably went into sleep (startup screen showed up after the rest) and reset whatever happened.
Bug or not, it got me pretty confused. I do admit it appears to be a minor issue and probably won't occur easily in real life situations.
Anyway, never happened again and it works like a champ... Except for the screen. I think I'm on my fourth now. I can't keep them for more than a couple of months until they start getting dimmed and unusable (the ribbon wire starts breaking near the glass) but that's a design issue. You can avoid touching the micro on board fire button but you can't avoid the metal button touching the cable. I use the device 24/7 so sooner or later the tiny movements will stress crack the ribbon cable near the glass (under the black isolation tape).
I still love it though