I noticed a discussion on this subject was closed but I'm experiencing a similar issue.
This is hands down the best tank when it works however after about a month the top gasket on the opening fell out and after trying to reinsert it I'm going thru coils daily due to insane burnt taste that is, quite honestly, making me sick physically. Have to keep opening and closing will get maybe 3 good hits and then painful burn inhale. I don't tighten the cap, maybe a half turn until snug but no difference. Is there a way to replace or resecure this gasket? It's the only replacement part I need that is not included. I'm not going to try and use an adhesive considering I'm "smoking" it. Also noticed small holes on the inside of the gasket, would that be for suction to hold it in place? Just purchased a new EXO today, hopefully my first one was just a lemon