Why is Vertexcolor warring appears?

I can not understand.
Why then a warning is displayed

"[Actor] (LOD [Index]) has hand-painted vertex colors that no longer match the original StaticMesh [StaticMesh]"

I’m loocking for Map checkError Page.
This → Map Check Errors | Unreal Engine Documentation

But I can still not understand.

The test results,
Mesh is re-imported when
The vertex color is automatically changed.
So the problem does not occur.

I want to know Why this warning is generated.

Plz Help Me!