I have the same problem. The quantity in the cart doesn’t update to the exact quantity that is int he cart. eg. i have 4 products on there and it said only “1″. The top part updates correct but the one in the black bar does not.
I have a similar problem. Using Magento 184.108.40.206 with HelloMinty theme. When I click Add to Cart, the product is added to the cart but right below the Checkout button it still says ‘You have no items in your shopping cart.’