@nuggethon thank you for a fast reply.
1) HTML template is successfully found.
2) We don’t use any email customizer plugin.
3) In the email log (using the plugin you recommended) I see no errors.
I did, however, managed to solve the issue by following the same example as offered on the topic.
In the email-manager.php, I changed
public function sanitize_email_template($class)
{
remove_action( 'email_header', array($class, 'woocommerce_email_header'));
remove_action('email_footer', array($class, 'woocommerce_email_footer'));
remove_action( 'email_order_details', array( $class, 'woocommerce_order_downloads' ), 10, 4 );
remove_action( 'email_order_details', array( $class, 'woocommerce_order_details' ), 10, 4 );
remove_action( 'email_order_meta', array( $class, 'woocommerce_order_meta' ), 10, 3 );
remove_action( 'email_customer_details', array( $class, 'woocommerce_customer_details' ), 10, 3 );
remove_action( 'email_customer_details', array( $class, 'woocommerce_email_addresses' ), 20, 3 );
}
to
public function sanitize_email_template($class)
{
remove_action( 'woocommerce_email_header', array($class, 'woocommerce_email_header'));
remove_action('woocommerce_email_footer', array($class, 'woocommerce_email_footer'));
remove_action( 'woocommerce_email_order_details', array( $class, 'woocommerce_order_downloads' ), 10, 4 );
remove_action( 'woocommerce_email_order_details', array( $class, 'woocommerce_order_details' ), 10, 4 );
remove_action( 'woocommerce_email_order_meta', array( $class, 'woocommerce_order_meta' ), 10, 3 );
remove_action( 'woocommerce_email_customer_details', array( $class, 'woocommerce_customer_details' ), 10, 3 );
remove_action( 'woocommerce_email_customer_details', array( $class, 'woocommerce_email_addresses' ), 20, 3 );
}
That seemed to work since I see all the order details now.