We have a new setting to work around this: set ‘Emissive Light Source’ on the component
By default Lumen culls small objects from Lumen Scene for realtime performance, but you can override this when you know it is an important source of light.
Also, what is the difference between the “Lumen Scene” and the “Surface Cache” view in the visualizer? Just the additional debug colors in the Surface Cache view? They seem identical otherwise.
Just the error coloring, we found it too distracting to be always present in Lumen Scene, where you are usually looking more at the lighting match rather than the Surface Cache coverage.