Just started yesterday. My phone gets hot (not Samsung fire hot, but pretty warm) when the battery level is plunging, which suggests that something is actually chewing up wattage. At least in my case.
I have no doubt there are battery issues that can be software (I remember IMAP issues back in the iOS4 days), but I think there is clearly a distinction between software bug battery drain issues (hot phone, slow consistent drop in charge) and this sudden shut down issue, battery percentage jumping by 10%/20% up and down when connected to a charger.
