I had the same issue with my 3880mAh battery mod
The batteries didn't normalize with every charge. Being that you have one, did you check the discharge and charge voltage range (3.7~4.2v). If so, is there only two terminals on the battery or more? If there is more, then the other ones tell the device the voltage level the battery is at. This is dangerous because you could be overcharging or under-discharging the battery.