Raytracing Shadow Distance on Foliage Actors

Is Skylight Raytraced Shadows supported on foliage spawned via a landscape material? I cannot seem to get spawned grass to cast RT shadows. Grass painted using the foliage painter does cast RT shadows. The spawned meshes are defined as InstancedGrass rather than InstancedStaticMeshes, so the console vars in this thread won’t work. Does anyone know a workaround (other than hand painting all the foliage)?