Aha! Excellent. I've run into this problem as well before and I think if you look in some of the HeaterMeter photos, you'll see a piece of blue painters tape over the USB ports in all of my test setups because it can cause all sorts of weird issues. Once the HeaterMeter is secured in the case, the LCD retention block is supposed to keep the two pieces from touching. It's one of those things where I went through the entire 4.3 design process iterations and everything was a go... and then I realized that this could happen.