ASP. NET Core MVC Перенаправление: просмотр дублированных и вложенных

Question

Я недавно столкнулся с приведенным ниже кодом для перенаправления в случае ошибок в устаревшем приложении, сделанном с ASP. NET Core MVC:

app.UseStatusCodePages(async context => {
    var response = context.HttpContext.Response;

    if (response.StatusCode == (int)HttpStatusCode.Unauthorized ||
        response.StatusCode == (int)HttpStatusCode.NotFound ||
        response.StatusCode == (int)HttpStatusCode.Forbidden)
        response.Redirect("/Account/Login");
});

Действие находится в AccountController.cs ниже:

[Authorize]
public class AccountController : BaseController
{
    public AccountController(
        UserManager<ApplicationUser> userManager,
        SignInManager<ApplicationUser> signInManager,
        ILogger<AccountController> logger,
        DbContext dbContext)
        : base(userManager, signInManager, logger, dbContext)
    {
    }


    // GET: /Account/Login
    [HttpGet]
    [AllowAnonymous]
    public async Task<ActionResult> Login(string returnUrl = null)
    {
        if (User.Identity.IsAuthenticated)
        {
            var user = await UserManager.FindByNameAsync(User.Identity.Name);
            return await UserManager.IsInRoleAsync(user, "Admin") ||
                   await UserManager.IsInRoleAsync(user, "Sales")
                ? RedirectToAction("Index", "Companies", new {Area = "Sales"})
                : RedirectToAction("Index", "Documents", new {Area = "Company", id = user.CompanyId});
        }

        return View();
    }


    // POST: /Account/Login
    [HttpPost]
    [AllowAnonymous]
    [AutoValidateAntiforgeryToken]
    public async Task<ActionResult> Login(LoginViewModel model, string returnUrl)
    {
        if (!ModelState.IsValid)
        {
            return View(model);
        }

        var result = await SignInManager.PasswordSignInAsync(
            model.Email,
            model.Password,
            model.RememberMe,
            true);

        if (result.Succeeded)
        {
            var user = await UserManager.FindByEmailAsync(model.Email);
            return await UserManager.IsInRoleAsync(user, "Admin") ||
                   await UserManager.IsInRoleAsync(user, "Sales")
                ? RedirectToAction("Index", "Companies", new {Area = "Sales"})
                : RedirectToAction("Index", "Documents", new {Area = "Company", id = user.CompanyId});
        }

        if (result.IsLockedOut)
        {
            return View("Lockout");
        }

        if (!result.IsNotAllowed)
        {
            ModelState.AddModelError(string.Empty, Resource.InvalidLoginAttempt);
        }

        return View(model);
    }

    // ...
}

_ViewStart.cshtml:

@{
    Layout = "_mainLayout";
}

Login.cshtml:

@using MySecretProject.Core.App_LocalResources
@using Microsoft.AspNetCore.Mvc.Rendering
@model MySecretProject.Core.Models.Account.LoginViewModel
@using Microsoft.AspNetCore.Mvc.Localization
@inject IViewLocalizer Localizer
@{
    ViewBag.Title = MySecretProject.Core.App_LocalResources.Views.Account.Login.Account_Login_Title;
}

@using (Html.BeginForm("Login", "Account", new { ViewBag.ReturnUrl }, FormMethod.Post, true, new { role = "form", @class = "form-horizontal contentPane2 contentPane2TopMargin" }))
{
    @Html.AntiForgeryToken()
    <div class="tab" style="width: 100%">
        <div id="TopHeader" class="documentTabHeaderTop">&nbsp;</div>
        <div class="container-fluid documentTitleHeader text-center documentTabHeaderTd-active">
            <div>Sign in</div>
            <div class="col-xs-12 col-sm-12 col-lg-12 headImage">@Html.ValidationSummary(true)</div>
        </div>
    </div>

    <div class="form-group has-feedback">
        <div class="col-lg-10 col-md-10 col-sm-10 col-xs-10 col-lg-offset-1 col-md-offset-1 col-sm-offset-1 col-xs-offset-1">
            <div class="input-group">
                <span class="input-group-addon"><i class="glyphicon glyphicon-envelope"></i></span>
                @Html.TextBoxFor(m => m.Email, new {@class = "form-control", @placeholder = "Email", aria_describedby = "EMailStatus"})
                @Html.ValidationMessageFor(m => m.Email, null, new { @class = "sr-only", id = "EMailStatus" })
            </div>
        </div>
    </div>
    <div class="form-group has-feedback">
        <div class="col-lg-10 col-md-10 col-sm-10 col-xs-10 col-lg-offset-1 col-md-offset-1 col-sm-offset-1 col-xs-offset-1">
            <div class="input-group">
                <span class="input-group-addon"><i class="glyphicon glyphicon-lock"></i></span>
                @Html.PasswordFor(m => m.Password, new {@class = "form-control", @placeholder = Resource.Password, aria_describedby = "PasswordBlock"})
                @Html.ValidationMessageFor(m => m.Password, null, new {@class = "sr-only", id = "PasswordBlock"})
            </div>
        </div>
    </div>
    <div class="form-group">
        <div class="text-center">
            <div>
                <input type="submit" id="ContinueButton" value="@Resource.Continue.ToUpper()" class="buttonItem buttonItem-valid"/>
            </div>
        </div>
    </div>
    <div class="form-group">
        &nbsp;
    </div>
    <div class="form-group">
        <div class="text-center">
            @Html.ActionLink(Resource.PasswordForgotten, "ForgotPassword", "Account", string.Empty, new { @style = "text-decoration: none;"})
        </div>
    </div>
}

Перенаправление ведет к представлению входа в систему, но вместо того, чтобы иметь Login.cshtml в _mainLayout.cshtml только один раз. Это происходит дважды.

Как этого избежать?

[EDIT]

Чтобы дать суть что происходит: