It's never happened to me but I wake up every morning to my phone saying passcode required. So I guess it restarts in the night on the chargeris this issue fixed already?
Give it back and replace itMy 6S started about two weeks ago telling me each morning that I needed to sign in with passcode after restart (although had not been restarted as far as I knew). About a week ago, started random freeze requiring two-button reboot. Upgraded to latest iOS today, now shuts down, I reboot, displays a scrolling corrupted screen, shuts down again... so have a completely non-functional phone. Not happy
iPhone 6s 64 gb Silver (Samsumg chip)
I have it for 11 days with no issue, last night my iphone was dead, on/off button not working, home button not working, try hard reset and iPhone went to life.
IOS 9.0.2
My iPhone was restored from Itunes backup, (not icloud) when I bought it.
no problems in first 11 days until I installed an old app from App store "NoiseWatch" version 2.0 (last update 02/01/2013)
I uninstalled it
I'd forgotten about this until I saw it pop up in my feed.Since 9.1 and several 9.2 betas I've not had this occur again in over a month now, and I had it several times on 9.0 and earlier 9.1 betas.
My ipad mini 4 does this from time to time.Apple acknowledged the iPad Pro having this issue but not the iPhone.
https://support.apple.com/en-us/HT6671