For some reason, the "add to cart" buttons don't want to redirect to the shopping cart page but rather just reload the same page. This was not always the case and I am not sure what settings have changed. The settings on "Configurations > Cart Settings > Add to Cart Redirect" is just "cart" and this is the same as when it was working.

The product is added to the cart and a new text line is added to the top of the page with the product name and then "...added to your shopping cart." witht he last part as a link to your shopping cart.