I don't know what coils you use. Hope it is not the bad kind Kanger dual coil losing its wick?Whenever I refill the tank, i cleanse the coil and everything around it.
If yes, an old Protank/EVOD single coil with the silicon cap of the dual coil extra on it can solve the leaking problem.
And if it is a new generation dual coil not losing its wick: All silicon caps and o-rings in place after cleaning job?