Man, that is lame to the max. It's completely comprehensible, of course, from an electrical point of view. But in an industry where 20% longer "battery life" is a huge marketing advantage, losing 40% of battery life is beyond embarrassing.
I guess the problem must be that some charging circuit component that is supposed to figure out that the battery is completely charged, and stop charging it, doesn't do its job. Or dies. Or something.
Man, that type of charge control circuitry has been a standard, solved problem for many decades. Somebody at Samsung or their suppliers needs to lose their head over this.
No. Its a rare manucacturing defect in the battery that allows anode and cathode to come in contact. Software or current limiting can’t fix that. See videos of crazy Russian guy stabbing li-ion battery with a knife for further info ;-)