The Shopify API that is used by GroovePacker Lite only has access to orders that are not Archived.
If you create shipping labels before scanning and packing orders, you'll need to make sure that the Shopify setting to automatically archive orders when they are fulfilled, is disabled. Here are the steps to do that:
First Navigate to Settings > Checkout
Next, scroll down to the Order Processing section and uncheck the box beside Automatically archive the order.