MAGETWO-65363: [GitHub][PR] Fix SALES_ORDER_TAX_ITEM_TAX_ID_ITEM_ID duplicates #8690

 - Merge Pull Request #8690 from mimarcel/magento2:fix/SALES_ORDER_TAX_ITEM_TAX_ID_ITEM_ID_duplicates

Author: Oleksii Korshenko

app/code/Magento/Tax/Model/Plugin/OrderSave.php

@@ -157,7 +157,7 @@ protected function saveOrderTax(\Magento\Sales\Api\Data\OrderInterface $order)
 
                         if (isset($ratesIdQuoteItemId[$id])) {
                             foreach ($ratesIdQuoteItemId[$id] as $quoteItemId) {
-                                if ($quoteItemId['code'] == $tax['code']) {
+                                if ($quoteItemId['code'] === $tax['code']) {
                                     $itemId = null;
                                     $associatedItemId = null;
                                     if (isset($quoteItemId['id'])) {