I have a question for you. I am having similar problems after the U3 update with alot of issues. One issue is the Edge lighting. I came across this video on you tube
If you look around 1.50 second mark there is an option in which the person changes the app colour for notifications of his edge lighting. However, i do not have that update of changing the colour since the new update, can you check yours settings to see if you can change your colour through the apps like the person in the video?
They removed edge lighting from a lot off apps as before Samsung music use to flash the edge lighting when playing music but now doesn't anymore 🙄