Cuz I smoke when I drink, at a bar with live music last Saturday after vaping and recharging once and letting it sit in case I noticed the case on the side where it sits got really, really hot. I checked it out and it was so hot I couldn't hold onto it. Let it sit and cool a bit, it worked but battery died. took out spare, hooked 'er up, light goes crazy, but it worked but it in case. Minute later that one did the same thing. My sweety also has one but hers did not go crazy. I kept switching them, charging, etc., and they kept going nuts for hours. Couldn't use em after an hour of this. After leaving the bar, all this craziness with the heat stopped. What's up with that? Oh, yeah, I'm waiting for customer service to respond. Been using this case for almost three months with little or not problem, loving it, refill with Johnson Creek rather than buy cartridges. Hmmm, maybe my batteries are going and need to buy more? Anyone ever have this same problem? Oh, yeah, first week with them I noticed a burning when I put it in my pocket connected. Customer service said motion will set them off, heats vaporizer, etc. When motorcycling I disconnect and that solves that but MUSIC? WTF?