Even in that case, at least screenspace should kick in and illuminate the scene, but even for that it looks way to dark - although there is some bouncing visible on the ceiling and the corner.
I wonder, if the glass is blocking it, or Lumen for whatever reason getting thrown off by glass and windows. There was another thread regarding glass and Lumen not working properly together:
https://forums.unrealengine.com/t/lumen-gi-with-glass-materials/602881/1