Request BrowserId : 1 not found it's likely the browser is already closed

При использовании метода EvaluateScriptAsync экземпляра класса ChromiumWebBrowser возвращает сообщение Request BrowserId : 1 not found it's likely the browser is already closed. Библиотека CefSharp. Вот фрагмент кода обработчика события loadingStateChanged:

    private async void _browser_LoadingStateChanged2(object sender, LoadingStateChangedEventArgs e)
    {
        if (!e.IsLoading)
        {
            JavascriptResponse resp = await _browser.GetMainFrame().EvaluateScriptAsync(
                @"document.getElementsByClassName('xt0psk2')[0]['href'];"
            );
        }
    }