I've just bought the Nokia 8 and there's something I'd like to know if is a feature or just my unit.
Whenever in a dark room I can see a screen backlight when glance is on, this also happens when then screensaver is on.
The screen on the above conditions is never off, and the glance feature in that case seems quite annoying (screen backlight on all the time)
Tbis happens because of the screen technology.
Nokia 8 has an IPS screen: in order to see anything on it (including glance), it needs to turn on the light under it. This is how all ips work.
The one that you've seen, were only the glance was visible is using an OLED or AMOLED (THIS IS EXCLUSIVE for SAMSUNG. OLED screen are generating their own light, for each poxel. This means thst only the needed pixel are visible. The black ones are turned of.
- fun fact: on oled you should keep dark walpapers to preserve some energy.
The rumored Nokia 9 will have OLED.