Blendshapes on combine meshes not working

Hi all, I'm new.

I have 2 gameObjects as body and head and I want to combine them to one (the head as submesh of the body). The body has avatar and the head has avatar and blendshape. They worked invidually.

When I combine them to one, I see the mesh run correctly with bones, but the blendshape on the head do not working.

I has checked that the head mesh still has blendshape. And when I create prefab for this object(body with head) then add it to the scene, the gameObject from prefab with correctly (blendshape is right).

Any solution here? Thank you
#Update: When I duplicate the combined gameObject to the new one. It worked. So any ideal ?