I've had kanger SubTank Mini for less than a week. I have the stock 1.2ohm OCC coil in it. Today after using it for a bit and then again after a 2 hour class it started leaking. Not like the whole tank was leaking but where the airflow chamber is it started leaking out the top and bottom. It seems like it stopped but I'm wondering if anyone else has had this issue with this tank before?