Woocommerce: Programatically Updating Order Status

When I try to programmatically update an order during a WP_Ajax hook. IE.

$order = wc_create_order($order_data);
$order->add_product( get_product( $membership_product_ids[0] ), 1 );
$order->set_address( $address, 'billing' );
$order->set_address( $address, 'shipping' );
$order_id = $order->id;
$order->update_status('completed');

I get the following errors:

Warning: DOMXPath::query(): Invalid expression in /wp-content/plugins/woocommerce/includes/libraries/class-emogrifier.php on line 299

Warning: DOMXPath::query(): Invalid expression in /wp-content/plugins/woocommerce/includes/libraries/class-emogrifier.php on line 299

Warning: Invalid argument supplied for foreach() in /wp-content/plugins/woocommerce/includes/libraries/class-emogrifier.php on line 302

Warning: DOMXPath::query(): Invalid expression in /wp-content/plugins/woocommerce/includes/libraries/class-emogrifier.php on line 299

Warning: DOMXPath::query(): Invalid expression in /wp-content/plugins/woocommerce/includes/libraries/class-emogrifier.php on line 299

Warning: Invalid argument supplied for foreach() in /wp-content/plugins/woocommerce/includes/libraries/class-emogrifier.php on line 302

If I remove that update_status function it does not error.

via Chebli Mohamed