Why is CompareAttribute failing on the client side in MVC 5 with AJAX form on subsequent submits?

Question

I'm using a mostly new jquery validation stack with ASP.NET MVC 5

• jquery-1.10.2
• jquery.validate 1.13.1
• jquery.unobtrusive-ajax.js 3.2.2
• jquery.validate.unobtrusive.js 3.2.2

I'm using an Ajax form with a partial view and for some reason the compare validation attribute works on the first post but not on subsequent posts. Here is my example:

Model

public class TestModel
{
    [Required]
    public string NewPassword { get; set; }

    [Required]
    [Compare("NewPassword")]
    public string ConfirmPassword { get; set; }
}

Index.cshtml

@model TestModel

<h2>Index</h2>

@Html.Partial("_TestForm", Model)

_TestForm.cshtml

@model TestModel

@using (Ajax.BeginForm("FormTester", "Test", new AjaxOptions{UpdateTargetId = "formContainer"}))
{
    @Html.AntiForgeryToken()

    <div id="formContainer">
        <div class="form-horizontal">
            <div class="form-group">
                @Html.LabelFor(model => model.NewPassword, htmlAttributes: new { @class = "control-label col-md-2" })
                <div class="col-md-10">
                    @Html.EditorFor(model => model.NewPassword)
                    @Html.ValidationMessageFor(model => model.NewPassword)
                </div>
            </div>
            
            <div class="form-group">
                @Html.LabelFor(model => model.ConfirmPassword, htmlAttributes: new { @class = "control-label col-md-2" })
                <div class="col-md-10">
                    @Html.EditorFor(model => model.ConfirmPassword)
                    @Html.ValidationMessageFor(model => model.ConfirmPassword)
                </div>
            </div>

            <div class="form-group">
                <div class="col-md-offset-2 col-md-10">
                    <input type="submit" value="Save" class="btn btn-default" />
                </div>
            </div>
        </div>
    </div>    
}

And finally my test controller

public class TestController : Controller
{
    public ActionResult Index()
    {
        return View(new TestModel());
    }

    // GET: Test
    public ActionResult FormTester(TestModel model)
    {
        if(ModelState.IsValid)
        {
            return PartialView("_TestForm");
        }

        return PartialView("_TestForm", model);
    }
}

Steps to reproduce,

1. Submit the form with valid data.
2. When the form is returned, there should not be any validation messages:
3. Change both fields again to be the exact same but with different data and attempt to submit:
4. Now the only way to submit the form again is to change the second field (or both) to be the original value:

I have no idea why this is happening or if there is even a workaround for this. Please help.