I have had no success dry burning these I just rebuild them now will try the rda soon rebuilding the stock coils is really easy though. Like the other guy said I think the grommet gets heated and is giving off the bad taste. if someone can tell me how to dry burn without the damage I would love to know. But like I said rebuilding them is easy.
Dry burning the stock coil will not burn the rubber grommet, because the leads that go from the wrap to the grommet are non-resistant. I do it all the time when rewicking a stock coil and have never had a problem. However if you rebuild the coil, it will burn the grommet as the entire wire will heat up, all the way down to the grommet.