ActionFilter Response.StatusCode is always 200

I'm trying to setup an action filter that only does something if the StatusCode of the HttpContext.Response is 302.

I would expect to be able to do this in the OnActionExecuting method, but the StatusCode is always 200.

ActionFilter code:

public class CustomFilter : IActionFilter
{
   public void OnActionExecuting(ActionExecutingContext context)
    {
        // do some setup
    }

    public void OnActionExecuted(ActionExecutedContext context)
    {
        if (context.HttpContext.Response.StatusCode == StatusCodes.Status302Found)
        {
            // never get here
        }
    }
}

My Action method:

public IActionResult Redirect()
{
    return RedirectToAction("Index", "Home");
}

And registering the ActionFilter in startup:

public void ConfigureServices(
    IServiceCollection services)
{
    services.AddMvc(
        options =>
        {
            options.Filters.Add(new CustomFilter());
        });
}

I have checked in the browser and it is correctly returning 302 and doing the redirect. I have also tried using the IAsyncActionFilter interface but had the same problem.

How can I apply my ActionFilter to () a redirected response?

And why is this not working as is?

: Whoops I had them the wrong way round. Actually I am still getting this issue though...