What can cause an ASP.NET MVC form to not submit / deserialize correctly?

It looks like it should work, but the form is being submitted with a model that hasn't been properly deserialized. Using latest ASP.NET MVC from nuget..NET 4.5

Very standard custom login view / controller.

View:

@model Alertera.Portal.Web.Models.RegisterViewModel
@{
    ViewBag.Title = "Register";
}

<h2>@ViewBag.Title.</h2>

@using (Html.BeginForm("Register", "Account", FormMethod.Post, new { @class = "form-horizontal", role = "form" }))
{
    @Html.AntiForgeryToken()
    <h4>Create a new account.</h4>
    <hr />
    @*@Html.ValidationSummary()*@
    <div class="form-group">
        @Html.LabelFor(m => m.UserName, new { @class = "col-md-2 control-label" })
        <div class="col-md-10">
            @Html.TextBoxFor(m => m.UserName, new { @class = "form-control" })
        </div>
    </div>


    <div class="form-group">
        @Html.LabelFor(m => m.FirstName, new { @class = "col-md-2 control-label" })
        <div class="col-md-10">
            @Html.TextBoxFor(m => m.FirstName, new { @class = "form-control" })
        </div>
    </div>

    <div class="form-group">
        @Html.LabelFor(m => m.LastName, new { @class = "col-md-2 control-label" })
        <div class="col-md-10">
            @Html.TextBoxFor(m => m.LastName, new { @class = "form-control" })
        </div>
    </div>

    <div class="form-group">
        @Html.LabelFor(m => m.Email, new { @class = "col-md-2 control-label" })
        <div class="col-md-10">
            @Html.TextBoxFor(m => m.Email, new { @class = "form-control" })
        </div>
    </div>

    <div class="form-group">
        @Html.LabelFor(m => m.Password, new { @class = "col-md-2 control-label" })
        <div class="col-md-10">
            @Html.PasswordFor(m => m.Password, new { @class = "form-control" })
        </div>
    </div>
    <div class="form-group">
        @Html.LabelFor(m => m.ConfirmPassword, new { @class = "col-md-2 control-label" })
        <div class="col-md-10">
            @Html.PasswordFor(m => m.ConfirmPassword, new { @class = "form-control" })
        </div>
    </div>
    <div class="form-group">
        <div class="col-md-offset-2 col-md-10">
            <input type="submit" class="btn btn-default" value="Register" />
        </div>
    </div>
}

      

        
        
        
      

    

Controller:

// POST: /Account/Register
[AcceptVerbs(HttpVerbs.Post)]
[AllowAnonymous]
[ValidateAntiForgeryToken]
public async Task<ActionResult> Register(RegisterViewModel model)
{
    if (ModelState.IsValid)
    {
        var user = new User
        {
            UserName = model.UserName,
            FirstName = model.FirstName,
            LastName = model.LastName
        };

        user.SetEmail(model.Email);

        var result = await _userManager.CreateAsync(user, model.Password);
        if (result.Succeeded)
        {
            _bus.Publish(new UserCreated(user));

            await SignInAsync(user, isPersistent: false);
            return RedirectToAction("Index", "Home");
        }
        AddErrors(result);
    }

    // If we got this far, something failed, redisplay form
    return View(model);
}

      

        
        
        
      

    

All messages come with an empty model or a fake token (it depends on whether I enable or disable validation). I'm just stumped and don't know where to look.

** EDIT **

If you disable antiforgery, ModelState is invalid, all fields in the model are empty, and error messages indicate that fields are required.

I am using Autofac with MVC extensions and the type bind is registered like this:

    builder.RegisterModelBinders(Assembly.GetExecutingAssembly());
    builder.RegisterModelBinderProvider();

      

        
        
        
      

    

Autofac works in general as the controller is created correctly and injected with the appropriate dependencies.

Edit 2: Created a custom binder, inheriting from DefaultModelBinder, per sentence so that I can see the transformation. It looks like the bindingContenxt model is null

The view model itself:

public class RegisterViewModel
{
  [Required]
  [Display(Name = "User name")]
  public string UserName { get; set; }

  [Required]
  [StringLength(100, ErrorMessage = "The {0} must be at least {2} characters long.", MinimumLength = 6)]
  [DataType(DataType.Password)]
  [Display(Name = "Password")]
  public string Password { get; set; }

  [Required]
  [DataType(DataType.Password)]
  [Display(Name = "Confirm password")]
  [Compare("Password", ErrorMessage = "The password and confirmation password do not match.")]
  public string ConfirmPassword { get; set; }

  [Required]
  public string Email { get; set; }

  [Required]
  public string LastName { get; set; }

  [Required]
  public string FirstName { get; set; }
}