fixing my merge

Author: Nil Portugués Calderó

src/Helpers/DataIncludedHelper.php

@@ -95,7 +95,7 @@ protected static function addToRelationshipsArray(
         foreach ($value as $propertyName => $attribute) {
             if (PropertyHelper::isAttributeProperty($mappings, $propertyName, $type)) {
 
-                $propertyName = DataAttributesHelper::transformToValidMemberName($propertyName);
+		$propertyName = DataAttributesHelper::transformToValidMemberName(RecursiveFormatterHelper::camelCaseToUnderscore($propertyName));
                 if (\array_key_exists(Serializer::MAP_TYPE, $attribute)
                     && count(array_values($attribute[Serializer::SCALAR_VALUE])) > 0
                     && \array_key_exists(Serializer::CLASS_IDENTIFIER_KEY, array_values($attribute[Serializer::SCALAR_VALUE])[0])) {