I set up a spotlight at the entrance to Sanctuary to help with the defense rating but the light keeps turning off. It has enough power and it is moving back and forth like it is supposed to do but the light just isn't on. The defense rating is still there so it isn't really negatively affecting anything I just like the aesthetic of my spotlight actually putting out light like it is supposed to do. Anyone know why it keeps doing this?

Did exact same thing and same issue. After putting down, light is fine. After traveling away or time passing day/night cycle, the light beam is no longer displayed.

Mini fix is pick up and plop down again in build mode and light gets re-enabled but hardly convenient. No sense of returning in the dark to your base and see the welcoming light.

No idea why though. Game bug, graphic driver bug, some combo of the two, etc

Very annoying. I've hooked it up to a power pylon with a switch so I can just turn it off and on again real quick to get it working again. Hope they fix this soon.

If you have a generator nearby you can just deactivate and reactivate the generator again using the action button rather than building a switch. This is what I do.