I didn't read this whole thread just the first few posts but I switched to a 3.7 14500 bottom fed mod recently and my
juice didn't taste very well either. since mine is not high powered I would think it has something to do with the epoxy used inside or the metal in my bottom feed injector. it is a hypo needle but I don't know my juice kinda tastes crappy like it has some sort of additive. just something I noticed so I thought I'd let u know in case you were just focusing on your 18650 staying so close to 4.2v for so long