I had this issue the first day that I got my note 5 on launch. I though it was due to the energy bar app that I installed on my phone, I removed it, restarted it and thought everything was fine. after a couple of hours it started happening again. I then installed nova launcher and action launcher to switch between the two, but I set up gestures to allow me to swipe the shade down using two fingers. That was fine, but it only works when you are at the home screen. so I deleted those and tried a restart, and it started happening again the next day. now the only other thing that I have on my phone that MAY contribute to it is the daydream, I have that set to power on using just the colors, and I sometimes notice it when I am awakening my phone from the daydream. and sometimes, just by turning the screen on.
As mfprince stated, the only way that I have been able to work around it is by locking the screen, swiping down the notification shade from the lock screen, and then unlocking the phone via swipe or fingerprint authentication. it is rather annoying none the less.