Error Value NaN Displayed in Cart Popover

[madamshai]

Hello!  I've been trying to find a way to get rid of a "NaN" value that keeps showing in the cart popover when you add a product to cart.  From my theme.js file it looks like the cart popover should be showing the "Quantity" followed by the "Product Title" but what renders is "NaN Product Title":

I inspected my site to see where the line of code comes from, and what I see is that the NaN is in the <h3> tag within the product title and no quantity is displayed:

  

I'm unsure what happened but my site is so heavily customized that I can not reach out to my theme developers for help.  Any insight on why the quantity isn't displaying or how I can simply remove the "NaN" would be so appreciated! 

Below is the details section of the cart popover from my theme.js file:

   showCartNotificationPopup: function(product){
      var addedQuantity = parseInt( $('.quantity__input', this.$container).val() );
      var title = product.product_title.length > 20 ? product.product_title.substring(0, 20) + '...' : product.product_title;
      var variant = product.variant_title == 'Default Title' ? false : product.variant_title;
      var image = slate.Image.getSizedImageUrl(product.image, '720x720');
      var unitPrice = this.$container.find('[data-product-unit]')[0] || null;
      if (unitPrice) { unitPrice = unitPrice.outerHTML; }

      var itemData = {
        item_count: addedQuantity,
        product_image: image,
        product_title: title,
        variant: variant,
        price: product.price,
        unit_price: unitPrice,
        price_formatted: slate.Currency.formatMoney(product.price, theme.moneyFormat)
      }