Unity - Code Show Message Test Bug

// Script name : Game_Event
public class Game_Event : Game_Base
{
    void Awake() {
        Game_Base.BaseAwake(); // Get Variables
    }

    [SerializeField]
    public Game_PageEvent pageEvent = new();

    bool isStart = false;
    bool IsStart {get {return isStart;}}

    public void EventStart() {
        if (IsStart) return;
        isStart = true;
        Debug.Log("Start Event !");
        gameParty.SetMoney(20);
        Debug.Log(gameParty.Money);
        // SceneManager.LoadSceneAsync("Scene_Message", LoadSceneMode.Additive);
        // GameManager.gameInterpreter.Pause();
        // Debug.Log(GameManager.gameInterpreter.isGamePause);
        GameManager.gameMessage.AddMessage("Salut sa va ?");
        GameManager.gameMessage.AddMessage("Tu va bien ?");
        GameManager.gameMessage.ShowDialogue();
    }
}

// Script name : Game_Message
public class Game_Message : MonoBehaviour
{

    public List<string> dialogue = new List<string>();
    public int index;
    public float wordSpeed = 0.06f;
    bool isMessage = false;

    public void AddMessage(string text) {
        dialogue.Add(text);
    }

    public void ShowDialogue() {
        if (!isMessage) {
            SceneManager.LoadSceneAsync("Scene_Message", LoadSceneMode.Additive);
            isMessage = true;
        }
    }

    public void HideDialogue() {
        SceneManager.UnloadSceneAsync("Scene_Message");
        dialogue.Clear();
    }

    public bool isNextMessage() {
        if (index < dialogue.Count) {
            index += 1;
            // Debug.Log(index);
            return true;
        }
        return false;
        // } else {
        //     isMessage = false;
        // }
    }
}

// Script name : Scene_Message
public class Scene_Message : MonoBehaviour
{
    Window_Base windowMessage;
    public TMPro.TMP_Text messageBox;
    int index = 0;

    void Awake() {
        windowMessage = GameObject.Find("WindowMessage").GetComponent<Window_Base>();
    }

    void Start()
    {
        windowMessage.enabled = true;
        messageBox.text = "";
        StartCoroutine(Typing());
    }

    void FixedUpdate() {
        if (Input.GetKeyDown(KeyCode.Space)) {
            if (GameManager.gameMessage.isNextMessage()) {
                // index++;
                messageBox.text = "";
                finishText = false;
                StartCoroutine(Typing());
            } else {
                GameManager.gameMessage.HideDialogue();
            }
        }
    }

    IEnumerator Typing() {
        Debug.Log("Affiche " + GameManager.gameMessage.dialogue[GameManager.gameMessage.index]);
        foreach(char letter in GameManager.gameMessage.dialogue[GameManager.gameMessage.index].ToCharArray()) {
            messageBox.text += letter;
            yield return new WaitForSeconds(GameManager.gameMessage.wordSpeed);
        }
    }

    bool finishText = false;
    void SpaceOneClickNoFinishText() {
        messageBox.text = GameManager.gameMessage.dialogue[GameManager.gameMessage.index];
        finishText = true;
    }
}

// Script name : Game_Interpreter
public class Game_Interpreter : MonoBehaviour
{

    bool gamePause = false;

    public bool isGamePause {get{return gamePause;}}

    GameState gameState = GameState.Map;
    enum GameState {
        Map,
        Menu,
        Battle
    }

    public void Pause() {
        gamePause = true;
        // Time.timeScale = 0f;
    }

    public void Resume() {
        gamePause = false;
        // Time.timeScale = 1f;
    }
}