I had this issue on my LG G2 where, randomly, the green LED status light would start flashing like there is a notification, when there is none. This is related to the Alarm. I posted this over in the G2 forums and I will post it here.
How to fix:
Clear all Notifications
Turn off Screen
(wait for notification light to blink) [confirm]
Turn on Screen
Go to Clock, disable Alarm
Double tap Status bar / Turn off Screen
(wait for notification light to NOT blink) [confirm] [fix]
Turn on screen and enable your Alarm.
The LED light should no longer blink for no reason.
Really kind of disappointed in the G4 software wise. On my G2, this issue and the lagging/FCing keyboard was huge issues that made me want to upgrade to the G4. Sad to say that even the newer software and newer hardware, these bugs are still present.