AbstractControl enable/disable does not pass emitEvent to this._updateAncestors()

<!DOCTYPE html>
<html>

  <head>
    <base href="." />
    <title>angular2 playground</title>
    <link href="style.css" rel="stylesheet" />
    <script src="https://unpkg.com/zone.js/dist/zone.js"></script>
    <script src="https://unpkg.com/zone.js/dist/long-stack-trace-zone.js"></script>
    <script src="https://unpkg.com/reflect-metadata@0.1.3/Reflect.js"></script>
    <script src="https://unpkg.com/systemjs@0.19.31/dist/system.js"></script>
    <script src="config.js"></script>
    <script>
    System.import('app')
      .catch(console.error.bind(console));
  </script>
  </head>

  <body>
    <my-app>
    loading...
  </my-app>
  </body>

</html>

/* Styles go here */

System.config({
  //use typescript for compilation
  transpiler: 'typescript',
  //typescript compiler options
  typescriptOptions: {
    emitDecoratorMetadata: true
  },
  paths: {
    'npm:': 'https://unpkg.com/'
  },
  //map tells the System loader where to look for things
  map: {
    
    'app': './src',
    
    '@angular/core': 'npm:@angular/core/bundles/core.umd.js',
    '@angular/common': 'npm:@angular/common/bundles/common.umd.js',
    '@angular/compiler': 'npm:@angular/compiler/bundles/compiler.umd.js',
    '@angular/platform-browser': 'npm:@angular/platform-browser/bundles/platform-browser.umd.js',
    '@angular/platform-browser-dynamic': 'npm:@angular/platform-browser-dynamic/bundles/platform-browser-dynamic.umd.js',
    '@angular/http': 'npm:@angular/http/bundles/http.umd.js',
    '@angular/router': 'npm:@angular/router/bundles/router.umd.js',
    '@angular/forms': 'npm:@angular/forms/bundles/forms.umd.js',
    
    '@angular/core/testing': 'npm:@angular/core/bundles/core-testing.umd.js',
    '@angular/common/testing': 'npm:@angular/common/bundles/common-testing.umd.js',
    '@angular/compiler/testing': 'npm:@angular/compiler/bundles/compiler-testing.umd.js',
    '@angular/platform-browser/testing': 'npm:@angular/platform-browser/bundles/platform-browser-testing.umd.js',
    '@angular/platform-browser-dynamic/testing': 'npm:@angular/platform-browser-dynamic/bundles/platform-browser-dynamic-testing.umd.js',
    '@angular/http/testing': 'npm:@angular/http/bundles/http-testing.umd.js',
    '@angular/router/testing': 'npm:@angular/router/bundles/router-testing.umd.js',
    
    'rxjs': 'npm:rxjs',
    'typescript': 'npm:typescript@2.0.2/lib/typescript.js'
  },
  //packages defines our app package
  packages: {
    app: {
      main: './main.ts',
      defaultExtension: 'ts'
    },
    rxjs: {
      defaultExtension: 'js'
    }
  }
});

//main entry point
import {platformBrowserDynamic} from '@angular/platform-browser-dynamic';
import {AppModule} from './app';

platformBrowserDynamic().bootstrapModule(AppModule)

//our root app component
import {Component, NgModule} from '@angular/core'
import {BrowserModule} from '@angular/platform-browser'
import { FormsModule, ReactiveFormsModule } from "@angular/forms";

import { FormComponent } from './form';

@Component({
  selector: 'my-app',
  template: '<fc></fc>'
})
export class App { }

@NgModule({
  imports: [ BrowserModule, FormsModule, ReactiveFormsModule ],
  declarations: [ App, FormComponent ],
  bootstrap: [ App ]
})
export class AppModule {}

import { Component } from '@angular/core';
import { FormGroup, FormControl } from '@angular/forms';

@Component({
    selector: 'fc',
    template: `<form [formGroup]="form">
    <input formControlName="c1">
    <br/>
    <input formControlName="c2">
</form>`
})
export class FormComponent {
    private c1: FormControl = new FormControl();
    private c2: FormControl = new FormControl();
    private form: FormGroup;
    constructor() {
        this.form = new FormGroup({
            c1: this.c1,
            c2: this.c2
        });
        this.form.valueChanges.subscribe(data => {
            console.log(data);
            if (data.c1 == '1') {
                this.c2.disable({ emitEvent: false });
            }
        });
    }
}