MAGETWO-44779: Issue with values for custom product attribute of type text area when product is updated via import

Author: Alex Bomko

app/code/Magento/CatalogImportExport/Model/Import/Product.php

@@ -2223,9 +2223,13 @@ private function _parseAdditionalAttributes($rowData)
 
         $attributeNameValuePairs = explode($this->getMultipleValueSeparator(), $rowData['additional_attributes']);
         foreach ($attributeNameValuePairs as $attributeNameValuePair) {
-            $nameAndValue = explode(self::PAIR_NAME_VALUE_SEPARATOR, $attributeNameValuePair);
-            if (!empty($nameAndValue)) {
-                $rowData[$nameAndValue[0]] = isset($nameAndValue[1]) ? $nameAndValue[1] : '';
+            $separatorPosition = strpos($attributeNameValuePair, self::PAIR_NAME_VALUE_SEPARATOR);
+            if ($separatorPosition !== false) {
+                $key = substr($attributeNameValuePair, 0, $separatorPosition);
+                $rowData[$key] = substr(
+                    $attributeNameValuePair,
+                    $separatorPosition + strlen(self::PAIR_NAME_VALUE_SEPARATOR)
+                );
             }
         }
         return $rowData;