I think 1/8 IC Fan could be onto something there, I've had failures of both balance boards in chargers (occasionally a pin will push back, or internal solder joint will crack), and also of balance connector pins on batteries. No real fault of the products, usually both after many (hundreds) of cycles of usage, but with a little resoldering and repinning everything works again.

Puffing and breaking the case sounds like a more legitimate failure though. I've definitely seen similar things with expensive lipos puffing somewhat quickly, but I've got a few turnigy blue lipos nearing 400 cycles and still running great + not puffed, albeit with the max capacity slowly having reduced after 250-300 cycles or so.