Default [Q] LG G2 rear LED not turning off

LG G2 rear LED won't turn off. It stays on all the time. The only time it turns off is when I turn off the phone.
I have been using this phone for 3 days and then this problem occurred. It takes a toll on the battery as well.
I have tried turning off the notification LED from display menu and it still stays on. Tried using some apps to turn off the rear LED but no success.
Is anyone else facing this problem? Can anyone suggest solutions for this?
Thank u.