Samsung
Edge Lighting Display Timing auf Samsung
Edge lighting on Samsung phones is set to Always by default, so the glow triggers for every notification regardless of whether the screen is on or off.
That can get in the way if you are actively using the phone and do not want a colored strip flashing at the edges while you read a message. It can also drain a bit of battery unnecessarily if you only care about the light as a locked-screen alert.
You control this timing in the Edge screen settings. Open Settings ➔ Display ➔ Edge screen ➔ Edge lighting ➔ Show Edge lighting and pick one of the three options: While screen is on, While screen is off or Always.
Choosing While screen is off limits the effect to locked-screen notifications, which matches what most people expect from an ambient light feature. While screen is on keeps the glow visible during active use, useful if you rely on it as a visual cue while gaming or watching video.
If Edge lighting does not appear at all after changing this setting, check that notifications are still enabled for the app in question and that Do Not Disturb is not active.