Lumen indirect lighting artifacts when far from world origin

Lumen seems to not be using Large World Coordinates somewhere. The Lumen Scene develops artifacts at large distances (5000 KM) from the world origin.

1. Download the Licensee's test case and open (see addl. info URL)
2. Open the map "/Game/LumenTest1" if it does not open by default
3. Enable the Lumen Overview viewmode
4. Focus on the setup actors and move closer for each, to see each setup in the Lumen Scene
5. Observe that the setup "Origin Setup" at the world origin and the setup "500k Setup3" located at (50,000,000, 0, 500) display the correct Lumen Scene
6. Observe that the setup "5 000k Setup2" located at (500,000,000, 0, 500) and the setup "10 000k Setup" located at (1,000,000,000, 0, 500) display significant banding and compression in the Lumen Scene.