The problem is Apple fanboyrs frantically taking selfies of themselves in their darknened mum's basement using the phone's camera and flash, causes the phone will overheat. The iOS 9 won't let you turn on the flash until the phone cool's down. This is actually a good thing as probably without it, the phone could experience a serious damage, but you would have thought that Apple would have factored in the narsassitic over use of the selfie function by Apple fans. 

Some users also report that the iPhone 6S and the 6S Plus are running significantly hotter than the iPhone 6 and 6 Plus. Users report that the iPhone 6s gets to a toasty 102 Fahrenheit / Celsius 38.9.

Last year's model would hit up to 90 Fahrenheit / 32.2 Celsius. People on that Redit thread noticed that the Facebook app was eating quite a lot of battery in the back ground. The overheating might have to do with the fact that Apple uses more Multiasking with the new iOS and probably needs time to master the battery use on the new iOS.. 

All this makes us wonder if the Apple A9 processor really is a 14nm processor. We will have to wait and see when this gets confirmed. Apple is probably on the phone name asking Qualcomm what it did when its Snapdragon 810 device started breathing fire.. 

This might be the reason that another chap was experimenting by putting the phone in the water for 30 minutes. The theory is that Apple has some kind of new water protection that it didn’t announce. Apple didn’t want to make a big deal about it, as otherwise people would be dipping their phones in the water just to make sure that they will work.  Then again if the iPhone 6s's catch fire they might have to.