I haven't flown my Parrot 2.0 for about 3 months. With Spring on the way I thought I'd get ready for some flying. I keep two batteries on charge using the Parrot charger. I just found one battery had swelled and popped it's case open. The other battery was beginning to swell up in the charger. Everything here is as-purchased Parrot, no modifications. Has anyone else had this problem?