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

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.