That cause that. It was "my app." That is I wrote it and it's not something you find on the stores.
So to figure this out I knew it was my app but it shows it could happen to other apps. To find it you either factory reset the phone but first just reboot the phone. If it still does it, start uninstalling apps till you find it or reach the point you have to factory reset.
Help! My new Galaxy S7 will flash on every time the time/minutes change. Even if it is resting on the desk and the screen is off, it will come on when time changes. I can't figure this out.