Material from Runtime Virtual Texture on at runtime spawned SplineMesh

Hi,
I create some SplineMeshComponents at runtime. The SplineMeshComponents gets a Material assigned. The Material takes a RuntimeVirtualTexture (of my Landscape). The problem is, that the SplineMeshComponents do not show the Material at runtime. It is blank. If I test the Material on a StaticMesh which is permanently in the scene, it works.
What are I am missing?

auto new_spline_mesh = NewObject<USplineMeshComponent>(this,
	USplineMeshComponent::StaticClass(),"",RF_NoFlags, nullptr,false,nullptr,nullptr);
new_spline_mesh->SetStaticMesh(MyMesh);
new_spline_mesh->SetMaterial(0,MyRuntimeVirtualTextureMaterial);
// set position, tangents aso. new_spline_mesh->SetStartPosition(...);
new_spline_mesh->UpdateMesh();
new_spline_mesh->SetCollisionEnabled(ECollisionEnabled::QueryAndPhysics);
new_spline_mesh->RegisterComponent();

Thanks in advance

So far, no one has any ideas? In order to rule out known causes that lead to similar problems, I will briefly write them down.

The bounds of the RVT volume are high enough to enclose the landscape and the generated target mesh. If they were not, the mesh would at least be black.

The RVT material works when the mesh is placed in the scene by the editor. It works when an Actor spawns with a mesh at runtime.

It does not work if an Actor spawns at runtime and then generates the mesh. The generated mesh is visible but shows no RVT material. If I use a traditional material it works!

I am grateful for any ideas

In case anyone else encounters the problem. The answer is simple. Activate “Used with Spline Mesh” in material Usage.