Appears to be working in Firefox but at least Chrome & Safari are broken. Should be a really recent regression so very few possible changes to blame...

Easiest repo: the todo list on our homepage.

var styles = null;
      var container = document.createElement('div');
      ReactDOM.render(<div style={styles} />, container);
      var stubStyle = container.firstChild.style;
      styles = {display: 'block'};
      ReactDOM.render(<div style={styles} />, container);
      expect(stubStyle.display).toEqual('block');
    });
    it('should update styles if updated to null multiple times', function() {
      var styles = null;
      var container = document.createElement('div');
      ReactDOM.render(<div style={styles} />, container);
      styles = {display: 'block'};
      var stubStyle = container.firstChild.style;
      ReactDOM.render(<div style={styles} />, container);
      expect(stubStyle.display).toEqual('block');
      ReactDOM.render(<div style={null} />, container);
      expect(stubStyle.display).toEqual('');
      ReactDOM.render(<div style={styles} />, container);
      expect(stubStyle.display).toEqual('block');
      ReactDOM.render(<div style={null} />, container);
      expect(stubStyle.display).toEqual('');
    });
    it('should skip reserved props on web components', function() {
      var container = document.createElement('div');
      ReactDOM.render(
        <my-component
          children={['foo']}
          suppressContentEditableWarning={true}
        />,