Download the licensee repro here - [Link Removed]
The issue is immediately visible in the project.
Licensee provided "how to repro" steps from scratch aswell:
"Create an empty level, add Directional Light, assign it as Atmosphere Light, enable Cast Cloud Shadow, add the Volumetric Cloud actor, and rotate the light to around horizon."
There's no existing public thread on this issue, so head over to AnswerHub just mention UE-119922 in the post.