When the device is locked (and you are on your lock screen) and you try to turn off the phone, my Sprint Note 8 asks for the password. When you have unlocked the phone and try to turn it off, it will not ask.
if device are on your lock screen ,then if you want to shut down your device, definitely it will ask your password/pattern/pin/fingerprint/iris/intelligent scanner etc..because of security of your device..it's normal don't worry
It's one of the security feature of your device..called Strong Protection..So when your device is locked and you want to turn it off, so it asks for pin or pattern to check whether the source is genuine or not..and when device is unlocked..means genuine source is already using that particular device and that's why there is no need of password..its quite normal..👍
