MAGETWO-71922: Error in Import Customers Main File with custom attribute.

Author: Bohdan Korablov

app/code/Magento/CustomerImportExport/Model/Import/AbstractCustomer.php

@@ -5,6 +5,7 @@
  */
 namespace Magento\CustomerImportExport\Model\Import;
 
+use Magento\ImportExport\Model\Import;
 use Magento\CustomerImportExport\Model\ResourceModel\Import\Customer\Storage;
 use Magento\ImportExport\Model\Import\ErrorProcessing\ProcessingErrorAggregatorInterface;
 
@@ -262,4 +263,16 @@ protected function getSelectAttrIdByValue(array $attributeParameters, $value)
             ? $attributeParameters['options'][strtolower($value)]
             : 0;
     }
+
+    /**
+     * Returns multiple value separator
+     *
+     * @return string
+     */
+    protected function getMultipleValueSeparator()
+    {
+        return isset($this->_parameters[Import::FIELD_FIELD_MULTIPLE_VALUE_SEPARATOR])
+            ? $this->_parameters[Import::FIELD_FIELD_MULTIPLE_VALUE_SEPARATOR]
+            : Import::DEFAULT_GLOBAL_MULTI_VALUE_SEPARATOR;
+    }
 }

app/code/Magento/CustomerImportExport/Model/Import/Address.php

@@ -5,7 +5,6 @@
  */
 namespace Magento\CustomerImportExport\Model\Import;
 
-use Magento\ImportExport\Model\Import;
 use Magento\ImportExport\Model\Import\ErrorProcessing\ProcessingErrorAggregatorInterface;
 
 /**
@@ -486,9 +485,7 @@ protected function _mergeEntityAttributes(array $newAttributes, array $attribute
      */
     protected function _prepareDataForUpdate(array $rowData)
     {
-        $multiSeparator = isset($this->_parameters[Import::FIELD_FIELD_MULTIPLE_VALUE_SEPARATOR])
-            ? $this->_parameters[Import::FIELD_FIELD_MULTIPLE_VALUE_SEPARATOR]
-            : Import::DEFAULT_GLOBAL_MULTI_VALUE_SEPARATOR;
+        $multiSeparator = $this->getMultipleValueSeparator();
         $email = strtolower($rowData[self::COLUMN_EMAIL]);
         $customerId = $this->_getCustomerId($email, $rowData[self::COLUMN_WEBSITE]);
         // entity table data
@@ -722,6 +719,7 @@ protected function _isOptionalAddressEmpty(array $rowData)
      */
     protected function _validateRowForUpdate(array $rowData, $rowNumber)
     {
+        $multiSeparator = $this->getMultipleValueSeparator();
         if ($this->_checkUniqueKey($rowData, $rowNumber)) {
             $email = strtolower($rowData[self::COLUMN_EMAIL]);
             $website = $rowData[self::COLUMN_WEBSITE];
@@ -740,9 +738,6 @@ protected function _validateRowForUpdate(array $rowData, $rowNumber)
                             continue;
                         }
                         if (isset($rowData[$attributeCode]) && strlen($rowData[$attributeCode])) {
-                            $multiSeparator = isset($this->_parameters[Import::FIELD_FIELD_MULTIPLE_VALUE_SEPARATOR])
-                                ? $this->_parameters[Import::FIELD_FIELD_MULTIPLE_VALUE_SEPARATOR]
-                                : Import::DEFAULT_GLOBAL_MULTI_VALUE_SEPARATOR;
                             $this->isAttributeValid(
                                 $attributeCode,
                                 $attributeParams,

app/code/Magento/CustomerImportExport/Model/Import/Customer.php

@@ -339,9 +339,7 @@ protected function _getNextEntityId()
      */
     protected function _prepareDataForUpdate(array $rowData)
     {
-        $multiSeparator = isset($this->_parameters[Import::FIELD_FIELD_MULTIPLE_VALUE_SEPARATOR])
-            ? $this->_parameters[Import::FIELD_FIELD_MULTIPLE_VALUE_SEPARATOR]
-            : Import::DEFAULT_GLOBAL_MULTI_VALUE_SEPARATOR;
+        $multiSeparator = $this->getMultipleValueSeparator();
         $entitiesToCreate = [];
         $entitiesToUpdate = [];
         $attributesToSave = [];