WPF calling Result of async method causing block

Question

I have a WPF appplication using Prism and I have found a extrage behaviour with Async method.

I have a class with async methods like this

public class ConfigurationManager(){
    public async Task<IList<T>> LoadConfigurationAsync<T>(){
        Tuple<IList<T>, bool> tuple = await LoadConfigurationItemsAsync();
        return tuple.Item1;
    }

    private async Task<Tuple<IList<T>, bool>> LoadConfigurationItemsAsync<T>(){
        await Task.Run(()  => 
        {

        });
        return new Tuple<IList<T>, bool>(configList.list, succes);
    }
}

And I needed to call them in sync form because I need the results in constructor of ViewModelManager and I try to use Result because is one of the ways to get the result in sync way.

public class ViewModelManager{
    private readonly ConfigurationManager _configManager;

    private void LoadConfiguration(){
        var config = _configManager.LoadConfigurationAsync().Result;
    }
}

For my surprise this causes the application to get blocked in the Result call, I know that Result is blocking but not for always, the return line of the method never gets executed. I tryed to call it using Task.Run and it works

private void LoadConfiguration(){
    var config = Task.Run(() => _configManager.LoadConfigurationAsync()).Result;
}

I don't know what's going on here and why calling result gets application blocked and why using Task.Run it works. It's like calling two tasks because the method is already returning a Task.