Did you store it fully charged? I've had a receiver pack puff up after sitting just two weeks at a full charge, learned that lesson. I think it's just luck of the lot mostly tho, I've had lipos puff two days after buying them and I've got some cheapo's that I've abused the crap out of that have yet to puff and one i ran completely dead so i jumped it with a car battery for about 6 min to get voltage in it so my charger would read it and it's been working solid for almost two months now.