Are you using Android 5.1.1?Hey! I have problem with light manager from GP. Installed this app on my Galaxy s6 edge, when message or missed call icon is apear, notification LED is light as I prefer, but when I clean missed call or read a message, popup SMS or icon missed call not disapear, so led light still. Only one way to stop it, is put down notification bar, and tap clean button. When light manager is uninstalled, everything is ok.
This is an expected issue after you have enabled "Enable 5.1.1 Workaround" in Light Manager.