Galaxy s5 Neo. Screen comes on intermittently
I had this issue with my S5 active. There was no immediate fix, but I was pretty sure it was caused by networks being found. I never saw it happen when I had wi-fi turned off, but I never really confirmed that this was the issue.

Also I had a friend who found 'Air wake up' was on, which was being triggered even without waving anything in front of the screen. So maybe check that.