Error at Checkout

This is the confirmation page from a test order. It shows the notice/error right below the order details. I have a screenshot if the link does not work.

This is the error:

Notice: Undefined variable: show_customer in /home/bestchea2/public_html/wp-content/plugins/woocommerce-smart-orders-page/templates/order/order-details.php on line 28

The page I need help with: [log in to see the link]