Because batteries are in a constant state of flux and will naturally transfer electrons, there is no 'on / off' switch, only a means of slowing down the transition.
All batteries do this and have done since batteries were invented, when have you ever charged anything up then left it for 3 months and have it still at 100%?
Feel free to go into that thread and continue the circular debate. One thing I'd add though is that turning the machine back on and then observing the percentage is in no way a beneficial methodology, the system will consume a comparatively high amount of power in starting up. To really test it you want to charge it then remove from the system, or open it up and attach a multimeter to the circuit. That's the only way to semi accurately observe the actual battery life.
Otherwise you're just looking at a software generated guestimate which changes dramatically in short spaces of time depending on current system use. And drawing conclusions of faulty batteries.
Just saying... If it's something that actually affects you then by all means have a peruse of forums. If not, then just use it and don't worry.
