Identical movable Actor rendered differently, maybe Indirect Lighting issue?

I’ve got the following Problem:

I got a scene with exclusively stationary Lights(some Spotlights directed at BounceCards and one Directional light) and some furniture which is intended to be movable, walls and architectural elements are static.
After Lightbaking everything looks just fine, except that identical movable actors are shaded quite differently as visible on the shelf in the screenshot!

When I move the darker shelf to the left it gets brighter until they look the same.

I guess it has something to do with the Indirect Lighting. Is there a way to prevent this or have this happening in a more gradual way, so it would create a gradient from bright to dark and not such a harsh contrast.

Maybe someone had the same Problem or could explain what is happening?

Any help is appreciated.


after some rest on the weekend and some searching I found the answer myself.

In the Detail Panel under Lighting(advanced) there is Indirect Lighting Cache Quality.
By default this is set to ILCQ Point, which seems to use only the idirect lighting sample next to the actors pivot.
If you change this to ILCQ Volume, it creates a nice blend from all samples next to the object.

In case you haven’t enough samples you can lower the Volume Light Sample Placement Scale in the world settings
Volume Lighting Samples can be shown under show > visualize.

Maybe this could be added to the Lighting Troubleshooting Wiki or the Documentation.