Yeah, mine did the same thing earlier today and I've only used a cartomizer on it since I got it a week ago but unlike the other responses about being too wet mine seemed to do it when the carto must have been going dry?? Filled it back up and all seemed OK. Anyways, it did stop doing that and seems OK now, just hope it stays that way and I also like it very much and def don't want to send it back as this also is my only HV device.
I was using a LR atomizer on my ego/Tornado before I got this Joker and I must say (IMHO) that doesn't even compare to the vape experience from this device not to mention the LR attys didn't last very long and started to get kinda expensive, so yeah, I don't wanna give it up either so hopefully it will work itself out.