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
var secondDiv = ReactTestUtils.findRenderedDOMComponentWithClass(
      refHopsAround,
      'second',
    );
    var thirdDiv = ReactTestUtils.findRenderedDOMComponentWithClass(
      refHopsAround,
      'third',
    );
    expect(refHopsAround.refs.hopRef).toEqual(firstDiv);
    expect(refHopsAround.refs.divTwoRef).toEqual(secondDiv);
    expect(refHopsAround.refs.divThreeRef).toEqual(thirdDiv);
    refHopsAround.moveRef();
    expect(refHopsAround.refs.divOneRef).toEqual(firstDiv);
    expect(refHopsAround.refs.hopRef).toEqual(secondDiv);
    expect(refHopsAround.refs.divThreeRef).toEqual(thirdDiv);
    refHopsAround.moveRef();
    expect(refHopsAround.refs.divOneRef).toEqual(firstDiv);
    expect(refHopsAround.refs.divTwoRef).toEqual(secondDiv);
    expect(refHopsAround.refs.hopRef).toEqual(thirdDiv);
    /**
     * Make sure that after the third, we're back to where we started and the
     * refs are completely restored.
     */
    refHopsAround.moveRef();
    expect(refHopsAround.refs.hopRef).toEqual(firstDiv);
    expect(refHopsAround.refs.divTwoRef).toEqual(secondDiv);
    expect(refHopsAround.refs.divThreeRef).toEqual(thirdDiv);
  });
  it('always has a value for this.refs', () => {
    class Component extends React.Component {