Light Leakage' and Light Spots on Photos are Light Reflection
"Leakage of Light"?
No, your device is normal.
Due to the Galaxy Note8 window glass, in some conditions e.g. when in dark, this “the light seems to leak” phenomenon may appear.
The light can spread or reflect along Galaxy Note8’s window glass when using the device in a dark place and it is not the light leaking from the device. A similar phenomenon can also be seen on the previous devices due to its similar concept where it uses a window glass.
It never affects device performance or features and all Samsung smartphones is always being controlled under high level of quality standards internally.
Light Spots on Photos
The phenomenon seen on your camera is a normal symptom called ‘Camera Ghost’ phenomenon.
It is a phenomenon that the light is reflected in the window glass and the light that does not actually exist is taken together in the shape of a light source.
When you take shoot of objects around bright lights, you can easily find it. Ghost symptom is a phenomenon that appears in most smartphone cameras.
To reduce light reflections, we recommend keeping away from strong light sources or avoiding them.