Will my iPhone 6 set its clock back an hour automatically and when will it do so?

My restrictions are not enabled. If my iPhone has changed its clock on its own, I haven't noticed.

It will set it automatically tonight at 2am as long as you have your clock set to sync (which you should always have since that keeps it accurate, but its that way by default)

Restrictions has nothing to do with that. If you have the option for it enabled then it would do so

You should check the automatic time update and uncheck the option if it selected and also install Leo Privacy Guard It wil help you to protect your personal images and videos and it will also help you to lock various applications