My new laptop, the Asus X750J (running on Linux Ubuntu 14.04), shows that the battery is on 70% while charging. When on battery, the indicator is working properly but as soon as I plug it in it goes to 70% and never changes.
It IS charging, but is this something to be concerned about?
update: the interesting thing is when I open the Battery settings it actually shows the right percentage, the problem is just the battery indicator.
Ok, I found the cause - the Ubuntu indicator shows the wireless mouse battery when the laptop is plugged in. It is an intelligent way of showing the most important battery status (if the laptop is plugged in, the mouse battery is the one most likely to fail) but this is very misleading. I have seen complaints dating back a couple of years, but this issue is still not fixed.