Low quality render with CreateMeshSection (UProceduralMeshComponent)

Hi, folks!
I have this simple code to draw procedural cube:

void AProcActor::AddTriangle(int32 V1, int32 V2, int32 V3)
{
	Triangles.Add(V1);
	Triangles.Add(V2);
	Triangles.Add(V3);
}

void AProcActor::CreateMesh()
{
	//6 sides on cube, 4 verts each (corners)
	
	//These are relative locations to the placed Actor in the world
	Vertices.Add(FVector(0, -100, 0)); //lower left - 0
	Vertices.Add(FVector(0, -100, 100)); //upper left - 1
	Vertices.Add(FVector(0, 100, 0)); //lower right - 2 
	Vertices.Add(FVector(0, 100, 100)); //upper right - 3
	
	Vertices.Add(FVector(100, -100, 0)); //lower front left - 4
	Vertices.Add(FVector(100, -100, 100)); //upper front left - 5

	Vertices.Add(FVector(100, 100, 100)); //upper front right - 6
	Vertices.Add(FVector(100, 100, 0)); //lower front right - 7

	//Back face of cube
	AddTriangle(0, 2, 3);
	AddTriangle(3, 1, 0);

	//Left face of cube
	AddTriangle(0, 1, 4);
	AddTriangle(4, 1, 5);

	//Front face of cube
	AddTriangle(4, 5, 7);
	AddTriangle(7, 5, 6);

	//Right face of cube
	AddTriangle(7, 6, 3);
	AddTriangle(3, 2, 7);

	//Top face
	AddTriangle(1, 3, 5);
	AddTriangle(6, 5, 3);

	//bottom face
	AddTriangle(2, 0, 4);
	AddTriangle(4, 7, 2);

	TArray<FColor> vertexColors;
	
	ProcMesh->CreateMeshSection(0, Vertices, Triangles, TArray<FVector>(), UVs, vertexColors, TArray<FProcMeshTangent>(), true);
	if (Material)
	{
		ProcMesh->SetMaterial(0, Material);
	}
}

Everything works, but in the game my cube quality is too low. What’s wrong?

Material is pretty simple: