I am having sort of the same issue. But mine is wether in a well lit room or dark room it doesn't matter.
I noticed that it usually happens when i receive a call, after the conversation when i hang up it does not go back to the home screen. all i get is a blank screen. the only way i can get it to generate the home screen again is by pulling down the status bar and going into the general settings and clicking home button again.
during this blank screen i can still see the status bar, and when i bring down the status bar i can see the nav buttons but they are unresponsive.
I also noticed this takes place sometimes after closing an app (noticed on netflix)
I am rooted on stock rom and TWRP recovery. Phone Model [LS-980 Sprint]
I immediately rooted so dont know if issue was there before root.
SOMEONE PLEASE HELP.