JavaScript Type Conversion Not A Number

I have a div with a data attribute that contains a date. When I retrieve said data value, it's not a date, but a string:

<div id="firstRow" class="form-group" data-expense-date="5/3/2016">
    <span>some stuff in here</span>
</div>

I'm retrieving the data element like so:

var currentDateString = $(this).data('expense-date');

I then am attempting to split the value into an array of strings:

var currentDateArray = currentDateString.split("/");

I then assign parts of the array as variables of my date I am trying to create:

var year = Number(currentDateArray[2].toString());
var month = Number(currentDateArray[0].toString());
var day = Number(currentDateArray[1].toString());

Interestingly enough, all three of my variables say that they are NaN. Thus, the declaration of my new Date variable is "Invalid Date":

var currentDate = new Date(year, month - 1, day);

I can do the following and it works just fine:

var dateString = "5/3/2016";
var dateStringArray = dateString.split("/");
var testDate = new Date(dateStringArray[2], dateStringArray[0] - 1, dateStringArray[1]);

It's only when I read the data attribute from the div element that sets the value to something that I do not know what it is.

I am debugging in Visual Studio and this is a screenshot of my Immediate Window trying to test the values:

Here is the complete example...my HTML:

<div class="col-md-6" id="detailPreview">
    <div class="panel panel-transparent" data-expense-date="5/2/2016">                             
        <div class="panel-heading">                                 
            <h3 class="panel-title">Monday, May 2, 2016</h3>                                 
            <div class="panel-actions">                                     
                <a class="panel-action icon wb-minus" data-toggle="panel-collapse" aria-expanded="true" aria-hidden="true"></a>                                 
            </div>                             
        </div>                             
        <div class="panel-body expense-date-body">                            
            <div class="panel" data-expense-detail-id="5e18bb2b-4671-490d-8769-5d3ea08134d8">                                 
                <div class="panel-heading">                                     
                    <h3 class="panel-title"><i class="icon wb-payment" aria-hidden="true"></i>Expense: Best Buy (ASUS Z555RA-3)</h3>                                    
                    <div class="panel-actions">                                         
                        <a class="panel-action panel-action-edit icon wb-settings" aria-hidden="true"></a>                                         
                        <a class="panel-action icon wb-minus" data-toggle="panel-collapse" aria-expanded="false" aria-hidden="true"></a>                                         
                        <a class="panel-action icon wb-close" data-toggle="panel-close" aria-hidden="true"></a>                                     
                    </div>                                 
                </div>                                 
                <!-- <div class="panel-collapse"> -->                                     
                <div class="panel-body">                                    
                    Business Name: Best Buy                                         
                    Location: Topeka, KS                                         
                    Purpose: Purchased replacement laptop for inventory                                     
                </div>                                 
                <!-- </div> -->                              
            </div>
        </div>                          
    </div>
    <div class="panel panel-transparent" data-expense-date="5/3/2016">                             
        <div class="panel-heading">                                 
            <h3 class="panel-title">Tuesday, May 3, 2016</h3>                                 
            <div class="panel-actions">                                     
                <a class="panel-action icon wb-minus" data-toggle="panel-collapse" aria-expanded="true" aria-hidden="true"></a>                                 
            </div>                             
        </div>                             
        <div class="panel-body expense-date-body">                             
            <div class="panel" data-expense-detail-id="49de85e2-b3ef-465d-8a61-cbc298b99d34">                                 
                <div class="panel-heading">                                     
                    <h3 class="panel-title"><i class="icon wb-payment" aria-hidden="true"></i>Expense: Wal-Mart (Scotch Tape)</h3>                                    
                    <div class="panel-actions">                                         
                        <a class="panel-action panel-action-edit icon wb-settings" aria-hidden="true"></a>                                         
                        <a class="panel-action icon wb-minus" data-toggle="panel-collapse" aria-expanded="false" aria-hidden="true"></a>                                         
                        <a class="panel-action icon wb-close" data-toggle="panel-close" aria-hidden="true"></a>                                     
                    </div>                                 
                </div>                                 
                <!-- <div class="panel-collapse"> -->                                     
                <div class="panel-body">                                         
                    Business Name: Wal-Mart                                         
                    Location: Topeka, KS                                         
                    Purpose: Purchased scotch tape                                     
                </div>                                 
                <!-- </div> -->                              
            </div>
        </div>                          
    </div>
</div>

My javascript:

$("[data-expense-date]").each(function () {
  if ($(this).data('expense-date') === dateShort.toString()) {
    parentDiv = $(this);
    return false;
  } else {
    debugger;

    // determine if this date is before or after the param date.
    //var dataExpenseDate = $(this).data('expense-date');
    var currentDateString = $(this).data('expense-date'); // "5/2/2016"

    var currentDateArray = currentDateString.split('/'); // [5,2,2016]
    //var yearString = currentDateArray[2];
    //var yearNumber = Number(yearString);
    var year = Number(currentDateArray[2]); // "2016" <-- NaN
    var month = Number(currentDateArray[0]); // "5" <-- NaN
    var day = Number(currentDateArray[1]); // "3" <-- NaN

    var currentDate = new Date(year, month - 1, day); // Invalid Date

    if (date > currentDate) {
        newDivInjectAfter = $(this);
    }
  }
});

UPDATE:
This only happens when I am using Internet Explorer (11). Edge, Opera, FireFox, and Chrome, ALL parse the values properly. Thanks for all of the responses guys, but I believe I have discovered a bug with IE.