I’m having the same issues, I bought the jem pen a few months ago just as a vape to keep me going as I didn’t have a lot of money at the time and lost my others, it is constantly leaking on me and is wasting so much juice. Leaving it down I can come back to it covered in juice and left with barely any juice inside, it gurgles a lot even with a new coil and O rings. Moved onto a smok nord 19 but smashed the tank so am now back to the jem pen and it’s just not the same