Maybe a bad balance board?
I don't know anything about TP chargers, but I do know I'll never touch another Reedy lipo for the rest of my RC life. Every reedy lipo that I have used and seen puffed within two uses. I always had balancing issues with mine and my bros 4s set his ESC on fire after it didn't balance right. Every other brand I have used in the same conditions had performed great (CRC, TrakPower, Orion, Thunder Power), so my guess is you have some bad reedys. Depending on how new they are you may be able to get them replaced. If not they will probably give you %50 credit towards some new ones like they offered me...I didn't take them up on it.