Fix WooCommerce "Nonce is Invalid" Issue

I need an experienced WooCommerce/WordPress developer to diagnose and permanently fix an intermittent “Nonce is invalid” error on my ecommerce website. The problem Customers sometimes receive a red “Nonce is invalid” error when trying to add products to their cart... (Budget: $30 - $250 AUD, Jobs: AJAX, CSS, Debugging, JavaScript, MySQL, PHP, Web Development, Website Optimization, WooCommerce, WordPress)