MAGETWO-68833: [Magento Cloud] - Paypal shows error in checkout but order still goes through but all subsequent orders fail afterwards

 - Removed Payflow Pro Express fields outdated mapping
 - Added string conversion for request fields

Author: YevSent

app/code/Magento/Paypal/Model/Api/AbstractApi.php

@@ -52,7 +52,9 @@ abstract class AbstractApi extends \Magento\Framework\DataObject
     /**
      * @var array
      */
-    protected $_lineItemExportItemsFilters = [];
+    protected $_lineItemExportItemsFilters = [
+        'name' => 'convertToString'
+    ];
 
     /**
      * @var array
@@ -354,6 +356,17 @@ public function getFraudManagementFiltersEnabled()
         return 1;
     }
 
+    /**
+     * Converts provided value to string.
+     *
+     * @param string|int|\Magento\Framework\Phrase $value
+     * @return string
+     */
+    public function convertToString($value)
+    {
+        return strval($value);
+    }
+
     /**
      * Export $this public data to private request array
      *

app/code/Magento/Paypal/Model/Api/PayflowNvp.php

@@ -773,11 +773,6 @@ protected function _exportLineItems(array &$request, $i = 0)
                 Cart::AMOUNT_SHIPPING => 'FREIGHTAMT',
                 'amount'              => 'PAYMENTREQUEST_0_ITEMAMT',
             ];
-            $this->_lineItemExportItemsFormat = [
-                'name'   => 'L_PAYMENTREQUEST_0_NAME%d',
-                'qty'    => 'L_PAYMENTREQUEST_0_QTY%d',
-                'amount' => 'L_PAYMENTREQUEST_0_AMT%d',
-            ];
             $request = $requestBefore;
             $result = parent::_exportLineItems($request, $i);
             /** @var Nvp $paypalNvp */