Question Blend Shape missing in animation clip copied to new mesh

I copied blend shape origin mesh to new mesh.
It seems to copy completely as you can see below screenshot. But It's not working in animation.

Mesh sourceMesh = _smRenderers[i].sharedMesh;

Mesh targetMesh = smr.sharedMesh;

Vector3[] deltaVertices = new Vector3[sourceMesh.vertexCount];

Vector3[] deltaNormals = new Vector3[sourceMesh.vertexCount];

Vector3[] deltaTangents = new Vector3[sourceMesh.vertexCount];

for(int shapeIndex = 0; shapeIndex<sourceMesh.blendShapeCount; ++shapeIndex)

{

    string shapeName = sourceMesh.GetBlendShapeName(shapeIndex);               

    if(targetMesh.GetBlendShapeIndex(shapeName) < 0)

    {

        int frameCount = sourceMesh.GetBlendShapeFrameCount(shapeIndex);

        for(int frameIndex = 0; frameIndex<frameCount; frameIndex++)

        {

              float frameWeight = sourceMesh.GetBlendShapeFrameWeight(shapeIndex, frameIndex);

              sourceMesh.GetBlendShapeFrameVertices(shapeIndex, frameIndex, deltaVertices, deltaNormals, deltaTangents);

              targetMesh.AddBlendShapeFrame(shapeName, frameWeight, deltaVertices, deltaNormals, deltaTangents);

          }

    }

}

this is my copy code.
(it refered https://extra-ordinary.tv/2020/09/07/copying-blendshapes-in-unity-with-a-script)

So I check animation clip in animation window. Blend shape in animation clip is missing.
I think link is broken during copy mesh to mesh.


can Unity Technology guys help me ?