message: transforms after PATCH - always return an array
diff: @@ -52,6 +52,8 @@ export const TransformRequestProcessors = {
  .then((raw: JSONAPIDocument) => {
  if (raw) {
  return handleChanges(record, serializer.deserializeDocument(raw, record));
  + } else {
  + return [];
  }
  });
  },
  