Okay, been paying close attention to how mine is behaving to hopefully help out here. No button issues whatsoever. In my car, it was acting funny for a while, several times, I got no vape upon pushing the button, and I was wondering if it was sticking. My theory on the drive was something about the shutoff too, because if I unplugged it and plugged it back in, it would work. Then I got home and tried it on my computer and on an AC to USB adaptor, and no problems at all on either.
That leads me to believe that problem I was having in the car is, in fact a voltage problem from my USB port and not the PT itself.
Belletrist, this may be a dumb question, but does the sizzle happen on all your carts? And is this a newly filled cart or one that's been in use? Reason I ask is that on my PTs (new model AND old model) if I have a freshly filled cart that is just a tad overfilled, I will hear the 'after sizzle' on the first few drags as (I guess) excess liquid is getting burned away, but it rectifies itself pretty quickly. (and you're welcome - I'm LOVING the blog!)