Invisible VolumetricCloud in Viewport Optimization

[GehtSieGarNixAn]

In the Youtube video from the Unreal Engine channel on [“Performance Optimization for Environments”][1] the “viewport optimization/Quad Overdraw” is used. It clearly shows the clouds as well. When I do the same with the same volumetric cloud actor as in the video, I don’t see any clouds. I only see the chess pattern in the sky. In fact, not a single optimization viewport works for clouds.

How can I use the optimization viewport for the volumetric clouds?

[GehtSieGarNixAn]

There’s another video demonstrating the optimization viewport should work for clouds. But it doesn’t explain why mine does not.

Reddit thread with the same question, but also no solution.