When creating an Element with a ref from inside of a constructor an error is thrown in production mode, but not in dev mode.

Here is a minimal sample:
https://jsfiddle.net/84v837e9/35/

An error, "Only a ReactOwner can have refs", should happen in dev and production modes.

This is happening in React 15.4
/**
 * Copyright 2013-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 *
 * @emails react-core
 */
'use strict';
var React = require('react');
var ReactDOMFeatureFlags = require('ReactDOMFeatureFlags');
var ReactTestUtils = require('react-dom/test-utils');
/**
 * Counts clicks and has a renders an item for each click. Each item rendered
 * has a ref of the form "clickLogN".
 */
class ClickCounter extends React.Component {
  state = {count: this.props.initialCount};
  triggerReset = () => {
    this.setState({count: this.props.initialCount});
  };
  handleClick = () => {
    this.setState({count: this.state.count + 1});
  };
  render() {