Hi
Have anyone faced the problem iphone 6s plus 64gb, power off by itself and the home button is very hot. Need to hard reset to power phone back on. My 3 weeks-old phone have the problem on ios 9.1. Read Apple forum, even 9.2 have the same issue. Seems like a hardware issue.
https://discussions.apple.com/thread/7247833?tstart=0

Seems like a hardware issue. Am thinking of sending in to check. This is the second time it happened.