Unreal 5.6 - Heterogenous Volumes indirect lighting setting doesn't work anymore

Development Rendering
1

Hi, all

I opened a 5.4 project in 5.6 (opening a copy), and these settings made no difference. The shadows in my VDB clouds remain dark.

r.HeterogeneousVolumes.MaxTraceDistance 50000
r.HeterogeneousVolumes.IndirectLighting 1

All settings for heterogeneous volumes in the project settings are also applied. Bug or are did I forgot something?

tia, urig