RealityKit won't show more than one DirectionalLight - swift

Question

I'm trying to create a simple 3D scene in RealityKit with two lights lighting a mesh from opposite sides. Everything seems to be working but both lights won't work at once. If I comment out light01, then light02 shows up fine.
Obviously from the type of project, you can tell I'm pretty new at this. What have I missed?
func makeUIView(context: Context) -> ARView {
//Configure ARView
let arView = ARView(frame: .zero, cameraMode: .nonAR,
automaticallyConfigureSession: true)
//Set background color
arView.environment.background = .color(.black)
let light01 = DirectionalLight()
light01.light.color = .red
light01.light.intensity = 30000
light01.light.isRealWorldProxy = true
light01.shadow?.maximumDistance = 10.0
light01.shadow?.depthBias = 5.0
light01.orientation = simd_quatf(angle: -.pi/1.5, axis: [0,1,0])
let light01Anchor = AnchorEntity(world: [0, 20, 0])
light01Anchor.addChild(light01)
arView.scene.addAnchor(light01Anchor)
//NOT WORKING
let light02 = DirectionalLight()
light02.light.color = .green
light02.light.intensity = 20000
light02.light.isRealWorldProxy = true
light02.shadow?.maximumDistance = 10.0
light02.shadow?.depthBias = 5.0
light02.orientation = simd_quatf(angle: .pi/1.5, axis: [0,1,0])
let light02Anchor = AnchorEntity(world: [0, 40, 0])
light02Anchor.addChild(light02)
arView.scene.addAnchor(light02Anchor)
//Create plane for floor
let floorMesh = MeshResource.generatePlane(width: 10, depth: 10)
let floorMaterial = SimpleMaterial(color: .white, isMetallic: false)
let floorEntity = ModelEntity(mesh: floorMesh,
materials: [floorMaterial])
let floorAnchor = AnchorEntity(world: [0, 0, 0])
floorAnchor.addChild(floorEntity)
arView.scene.addAnchor(floorAnchor)
let sphereMesh = MeshResource.generateSphere(radius: 1.5)
let sphereMaterial = SimpleMaterial(color: .white,
roughness: 0.9,
isMetallic: false)
let sphereEntity = ModelEntity(mesh: sphereMesh,
materials: [sphereMaterial])
let sphereAnchor = AnchorEntity(world: [0, 1.5, -4])
sphereAnchor.addChild(sphereEntity)
arView.scene.addAnchor(sphereAnchor)
//Camera
let camera = PerspectiveCamera()
let cameraAnchor = AnchorEntity(world: [0, 1, 1])
cameraAnchor.addChild(camera)
arView.scene.addAnchor(cameraAnchor)
return arView
}

Answer 1

About DirectionalLight in RealityKit 2.0
RealityKit scene can contain up to nine lights. Eight of them could be dynamic lights of different types – PointLights, SpotLights, and a DirectionalLight, and one of them is image-based light (IBL). However, RealityKit supports just ONE DirectionalLight (a.k.a. virtual Sun) per scene.
In addition to the above, it makes sense to note that the position of the DirectionalLight in the RealityKit scene doesn't matter and DirectionalLight has .isRealWorldProxy instance property which, if set to true, cast shadows on virtual content without illuminating anything in the scene. You can use it to create shadows on occlusion materials that accept dynamic lighting.