Deep linking and urlscheme when app has not started (iOS)

How do you enable deep links to work before an app has started? l
urlscheme variable passing does not seem to work when app first opens (cold starts)…

private void Awake()
{
    if (Instance == null)
    {
        Instance = this;
        Application.deepLinkActivated += onDeepLinkActivated;
        if (!string.IsNullOrEmpty(Application.absoluteURL))
        {
            // Cold start and Application.absoluteURL not null so process Deep Link.
            onDeepLinkActivated(Application.absoluteURL);
        }
        // Initialize DeepLink Manager global variable.
        else deeplinkURL = "[none]";
        DontDestroyOnLoad(gameObject);
    }
    else
    {
        Destroy(gameObject);
    }
    print(">>> " + Application.absoluteURL);
}