Is this cascade shadow? Where is the solution?

The balls are movable, Lights around them are Staic. LightmassCharacterIndirectDetailVolume has been put here
and the project has been built

I find that the ball far away from the camera is brighter

How to fix this problem?

in the viewport’s upper left corner do Show->Visuailze->Show Volume Lighting Samples
This will visualize the samples, that define how lightmass affects moving object.
Probably you do not have enough of them. Also make sure to place Lightmass importance volume in your scene.

To get shadows from moving objects, change your light type from static to stationary.