Hello,
I have checked your site and found that you still have outdated WooCommerce email template overrides in your child theme:
– wp-content/themes/woodmart-child/woocommerce/emails/admin-new-order.php
– wp-content/themes/woodmart-child/woocommerce/emails/customer-completed-order.php
These files are overriding the default WooCommerce email templates and are currently outdated. You need to update these template files to match the latest WooCommerce version. You can compare them with the latest templates provided by WooCommerce and merge any customizations into the updated files.
As a test, you can temporarily rename these files and check whether the email issue is resolved.
Best Regards