I am having same issue since 4 days.
Phone just black out having 40% battery. It did not switch on for hours then it came back on with battery drain and network issue.
I did factory reset twice and even change firmware from SA to INS but no solution.
The phone rans hot and consumes about 25% battery overnight at idle screen off.
Should samsung deploy a fix or a major update? As i think it is not hardware related as several users are having this problem.
We would suggest you to follow the mentioned steps to resolve the issue:
For battery drainage issue follow the given link- http://www.samsung.com/in/support/skp/faq/1101689
1) Check Network mode and set it to Auto Connect. (Settings > Connections > Mobile Network > Network mode > Select LTE/3G/2G auto connect)
2) Search for the Network Manually by the steps as mentioned:
Settings > Connections > More Networks > Mobile Networks > Network Operators > Select Manual Search.
3) Check via another SIM card in the device.
4) Reset network settings (Settings > General Management > Reset > Reset network settings).
Note: Kindly once coordinate with the network service provider,
If still issue persists, kindly visit nearest service center for physical inspection of your device. Service center personnel will provide you the further resolution.
Follow the link mentioned below-
Team Samsung Members