In the couple of weeks I have had the PBP, my practice is to leave them in the case (which is generally not plugged in) overnight. Twice now, I have awoken to find the headphones at near zero charge (1% typically), while the case itself is still mostly charged (once was at 95%, once at 50-something percent). Can anyone figure out why this is happening and whether I can prevent it from happening again? Is it possible something is faulty here?