Hi @reinermaenner Thanks for the detailed question and sample code. Posts like yours help us easily recreate and troubleshoot questions! This may be a bug, but our teams will need to further investigate. Please consider filing a bug using Feedback Assistant. I think it may be related to triggering the animation during scene setup, but can't say for certain. In the meantime, I was able to work around the issue, by invoking the animation in a task after the parent child relationships are established. Here's the revised code. import SwiftUI import RealityKit import RealityKitContent struct ImmersiveView: View { @Environment(AppModel.self) var appModel let boardHeight: Float = 0.1 let boxHeight: Float = 0.3 var body: some View { RealityView { content in let boardEntity = makeBoard() content.add(boardEntity) let mesh = MeshResource.generateBox(width: 0.3, height: boxHeight, depth: 0.3) var material = UnlitMaterial(); material.color.tint = .green let boxEntity = ModelEntity(mesh: mesh, materials: [material]) boardE