Transition animation character in SceneKit

Question

I try to make transitions between the animations of a character but I can't quite understand...

To start any of my character without animation in position T

Then I import a walking animation and add it to my character

To begin with, my character starts walking but his arms remain in T... why?

Here is my code

    import PlaygroundSupport
    import SwiftUI
    import SceneKit

    let scene = SCNScene(named: "Agnes.scn")!
    let model = scene.rootNode
    let speed:TimeInterval = 5
    var run:SCNAnimationPlayer?
    var dance:SCNAnimationPlayer?
    var idle:SCNAnimationPlayer?
    var anim:SCNAnimationPlayer?

    struct CharacterView: UIViewRepresentable {

func makeUIView(context: Context) -> SCNView {
    let scnView = SCNView(frame: .zero)
    scnView.scene = scene

scnView.autoenablesDefaultLighting = true
    scnView.allowsCameraControl = true
    return scnView
}
    
    func updateUIView(_ view: SCNView, context: Context) {
    }
}

struct ContentView: View {
    @State private var isRunning = false
    @State private var isSalsa = false
    @State private var isIdle = false

    var body: some View {
        VStack {
            CharacterView()
                .frame(height: 300)
            
            HStack {
                Button(action: {
                    anim?.stop(withBlendOutDuration: speed)
                    run?.play()
                    anim = run
                }) {
                    Text("Running")
                        .padding()
                        .background(Color.blue)
                        .foregroundColor(.white)
                        .cornerRadius(10)
                }
                
                Button(action: {
                    anim?.stop(withBlendOutDuration: speed)
                    dance?.play()
                    anim = dance
                }) {
                    Text("Salsa")
                        .padding()
                        .background(Color.green)
                        .foregroundColor(.white)
                        .cornerRadius(10)
                }
                
                Button(action: {
                    anim?.stop(withBlendOutDuration: speed)
                    idle?.play()
                    anim = idle
                }) {
                    Text("Idle")
                        .padding()
                        .background(Color.orange)
                        .foregroundColor(.white)
                        .cornerRadius(10)
                }
            }
            .padding(.top, 20)
        }
        .onAppear {
            // Mettez ici le code pour charger les animations du personnage
            run = Page_Contents.animation(name: "Running.usdz")
            dance = Page_Contents.animation(name: "Dancing.usdz")
            idle = Page_Contents.animation(name: "Idle.usdz")
            
        }
    }
}

func animation(name:String) -> SCNAnimationPlayer
{
    var animation:SCNAnimationPlayer? = nil
    
    let fichier = SCNScene( named: name )!
    fichier.rootNode.enumerateChildNodes { (child, stop) in
        if !child.animationKeys.isEmpty {
            animation = child.animationPlayer(forKey: child.animationKeys[0])
        }
    }
    
    let cle:String = name
    model.addAnimationPlayer(animation!, forKey:cle)
    animation?.animation.isRemovedOnCompletion = false
    animation?.animation.blendInDuration  = speed
    animation?.animation.blendOutDuration = speed
    animation?.animation.isRemovedOnCompletion = false
    
    animation?.stop()
    
    return animation!
}

PlaygroundPage.current.setLiveView(ContentView())

And my Playground

Thanks !