Volumetric Clouds look flat with Beer shadow maps

Official doc for Volumetric Clouds says that you can use Beer shadow maps instead of Ray marching the volume shadow https://docs.unrealengine.com/en-US/BuildingWorlds/LightingAndShadows/VolumetricClouds/index.html

But when I disable Ray marching the volume shadow clouds just become flat - all shadows are gone.

Ray marching the volume shadow ON:

Ray marching the volume shadow OFF: (suppose to turn on Beer shadow maps instead)