Just got my note 5. And noticed that when I look at it in the lights at an extreme angle, the glass looks wavy and has a clear rainbow effect to it. Is this normal? I can't remember my note 3 or 4 being like this.
If you are within your 14 day grace period, have them swap it out for free. If they want to charge you a restocking fee (they shouldn't because your phone is defective), contact Samsung for a replacement device via manufacture warranty. If you are out of your 14 day grace period, go straight to contacting Samsung.