I also have the same problem with the edge light not working. It was working fine couple days ago when I bought it last week.
I also have the problem work on Allway on display, it seem doesn't work correctly, I try to double tap on the screen, never work.
This is a US unlock version.
Model number SM-N960U1
Serial number < Hidden >
IMEI < Hidden >
I just did a reset setting this morning and everything seem to working properly now (for both edge lighting and Allway on display).
Note.. the edge lighting seem to work only with the apps that the phone has suggested (Viber and messages) Gmail didn't work not sure Facebook either.
Tuesday November, 27 2018
My edge lighting has not worked since reciept of phone. All combination of settings have been tried and all software is current.
Model number SM-N960U1
Serial number RF8KA101NAX
Build number: M1AJQ.N960U1UEU1ARJ5
Baseband version: N960U1UEU1ARJ5
US version, unlocked. T-Mobile is the carrier.
I found the solution for the Edge lighting not working and it works 100%. And the best part is you dont need to have the annoying popups (for example on Whatsapp) activated. Tested on S8 and S9.
First thing you have to do is install the Light Flow app (by the way, pretty useful for modifying your LED light). After you install and activate it go to "notification settings" and there you can find a list of apps you want to modify your LED light for. Add the app you want your Edge lighting to work (Whatsapp in my case), then press those 3 dots on the right of the listed app and press "settings"
Now click on the "notifications" tab next to the "trigger" tab on top.
Here you have to click the fields "exclude from sleep mode" and "switch screen on".
Your work with Light Flow app ends here.
Now go to your phone settings to display-edge screen-edge lighting. Go to "manage notifications" on the bottom and add the Light Flow app. Once it is done go to edge lighting style-color-custom color. Edit the light color you want for the Light Flow app and you are done!
Basically what happens is when you receive an Whatsapp message (or any app you choose) Light Flow app will initiate a virtual popup (nothing visible on the screen) and that will trigger the Edge lighting to work on the screen that is off.
Hope it helps and if you need any questions let me know
started after last update.... with Textra app. no worky. .. . with Samsung messaging app works perfectly fine. tried 2 other 3rd party apps and didn't work unless screen was already on. lame