1.Vaping setting is improper.
3.Sitting for a long time after refilling.
1.Please try to vape at a appropriately high wattage which is recommended on the coil during vaping. It may encounter the leaking issue if the liquid on the coil hasn't been atomized on time with low wattage.
2.Please do not set it for a long time since the cotton will absorb liquid and will split from the mouth piece while you inhale it. In this case, please upside down the tank and shake the inside spare juice off.