LG G5 european version at least
Here what i did about the heating issue:
I completely dissasembled my phone down to the motherboard, nicely disconnected all devices with a plastic pry tool from the motherboard. Just on a personal to those who do wonder, all the shielding on the SOC`s are not soldered to ground, they can be opened simply with a prying tool(do be very carefull when opening the shields). I literally applied MX4 thermal paste on the soc`s (crazy dude aint i?) spreaded around so the coat is even especially on the ARM cpu which is beneath, basically on the back of the phone, which is why you feel it getting more hot there, then put the shielding back together screws back in, cover, battery in, turned the phone back on, cleared dalvik cache and rebooted the phone to system. Why clearing dalvik? because after the system restarts it regenerates the dalvik cache on all apps, before actually going into android, and this operation heats up the cpu intensively if you dont have any thermal paste on there. But since mine had...while it was regenerating the dalvik cache, i felt no heat at all...and i think the battery stays a bit longer aswell now...