The code

``` javascript
class Comp extends React.Component {
  componentWillMount() {
    setTimeout(() => {
      this.setState({});
    });
  }

  render() {
    return <div onClick={() => {}} />;
  }
}

ReactDOMServer.renderToString(<Comp />);
```

produces errors:

> Warning: React can't find the root component node for data-reactid value `.0`. If you're seeing this message, it probably means that you've loaded two copies of React on the page. At this time, only a single copy of React can be loaded at a time.
> 
> Uncaught TypeError: Cannot read property 'firstChild' of undefined

But if I remove `onClick` handler the errors go away...

See demo: http://codepen.io/dened/pen/YyByYr

}
  },
  /**
   * Overridden in shallow rendering.
   *
   * @protected
   */
  _replaceNodeWithMarkup: function(oldHostNode, nextMarkup, prevInstance) {
    ReactComponentEnvironment.replaceNodeWithMarkup(
      oldHostNode,
      nextMarkup,
      prevInstance
    );
  },
  /**
   * @protected
   */
  _renderValidatedComponentWithoutOwnerOrContext: function() {
    var inst = this._instance;
    if (__DEV__) {
      if (this._debugID !== 0) {
        ReactInstrumentation.debugTool.onBeginLifeCycleTimer(
          this._debugID,
          'render'
        );
      }
    }
    var renderedComponent = inst.render();
    if (__DEV__) {
      if (this._debugID !== 0) {