This has happened with 3 different rdas. I vape on it for about four months, changing the coils and wick every two weeks or so. Nothing is wrong with it. Tastes great. Then after I change the coils and wick one day the rda has a metallic taste and the smell is just burnt. I've had this happen to me 3 different times on 3 different rdas. I have no idea why this is happening. Can somebody please help me??