I´ve been encountering this very weird issue where I have a blueprint that has a bunch of different modular space station models and a lot of dynamic lights (spot and point types) with small radius and no shadow casting because I´m aiming for VR. I´m getting a really good performance but when I move sometimes I see this odd light culling or change. This is happening when I have a lot of these blueprints in the scene but is not happening when I only have one. I´ve been testing a lot of things but I don´t know if there are some sort of limit in the engine that is causing this.
I was searching for this issue myself for a resolution, I’m not sure if you and I have the exact same problem, but I managed to resolve my problem by setting the Source Length and Source Radius back to 0, which fixed this strange issue where the light would be culled out or act strangely. They are 0 by default so unless you’ve adjusted these values, we may have a different issue. Of course, it’s been a long time since you posted this so I’m sure you may have solved it by now.
I’m glad it helped! Sorry that you went for so long without an answer, but I thought I’d post it just in case, and for others who may be experiencing the same issue we had. Hopefully this is fixed in a later version of UE4.