Setting> Apps> All> uninstall app, then go back in to Settings> Apps> All > and DISABLE the app. This will keep it quiet until it automatically installs updates then you will have to repeat the process. I Usually have to uninstalled disable mine once to twice a week. Its annoying as all get up it wont stay disabled. I hope its just a glitch in my phone and yours works perfectly.
Go to Settings > Apps > Look for Lumen toolbar and uninstall it.
Let me know if it works. :)