Push notification is not working on Background

I'm using native firebase plugin's push notification feature.

Current behavior:

It is working fine with the foreground.But when the app is in the background and I try to tap the notification it shows undefined.Please see the video below.I have tested this on Anroid device.

Expected behavior:

When I tap the notification message it should open the app and show the message correctly.

Video

app.component.ts

constructor(public platform: Platform)
{
    platform.ready().then(() => {
           this.onNotificationOpen();
      });
}

onNotificationOpen(): void {
        if (this.platform.is('cordova')) {
            this.firebase.onNotificationOpen()
                .subscribe(res => {
                    if (res.tap) {//background mode
                        console.log(res.body);
                        this.showAlert(res.body);
                    } else if (!res.tap) {//foreground mode
                        console.log(res.body);
                        this.showAlert(res.body);
                    }
                });
        }
    }

        showAlert(message: string): void {
        let alert = this.alertCtrl.create({
            title: 'Push Notification',
            subTitle: message,
            buttons: ['OK']
        });
        alert.present();
    }

package.json

{
  "name": "ionic-hello-world",
  "author": "Ionic Framework",
  "homepage": "http://ionicframework.com/",
  "private": true,
  "scripts": {
    "clean": "ionic-app-scripts clean",
    "build": "ionic-app-scripts build",
    "ionic:build": "ionic-app-scripts build",
    "ionic:serve": "ionic-app-scripts serve"
  },
  "dependencies": {
    "@angular/common": "4.1.0",
    "@angular/compiler": "4.1.0",
    "@angular/compiler-cli": "4.1.0",
    "@angular/core": "4.1.0",
    "@angular/forms": "4.1.0",
    "@angular/http": "4.1.0",
    "@angular/platform-browser": "4.1.0",
    "@angular/platform-browser-dynamic": "4.1.0",
    "@ionic-native/core": "3.6.1",
    "@ionic-native/device": "3.6.1",
    "@ionic-native/facebook": "^3.10.0",
    "@ionic-native/firebase": "^3.10.3",
    "@ionic-native/keyboard": "^3.10.3",
    "@ionic-native/splash-screen": "3.6.1",
    "@ionic-native/status-bar": "3.6.1",
    "@ionic/cli-plugin-cordova": "^1.2.0",
    "@ionic/cli-plugin-ionic-angular": "^1.2.0",
    "@ionic/storage": "2.0.1",
    "@ngrx/core": "^1.2.0",
    "@ngrx/store": "^2.2.1",
    "d3": "^4.7.4",
    "firebase": "^3.7.5",
    "ionic-angular": "3.2.1",
    "ionicons": "3.0.0",
    "moment": "^2.18.1",
    "pouchdb": "^6.1.2",
    "pouchdb-adapter-cordova-sqlite": "^2.0.2",
    "rxjs": "5.1.1",
    "sw-toolbox": "3.6.0",
    "zone.js": "0.8.10"
  },
  "devDependencies": {
    "@ionic/app-scripts": "1.3.7",
    "@ionic/cli-plugin-cordova": "1.2.1",
    "@ionic/cli-plugin-ionic-angular": "1.2.0",
    "typescript": "~2.2.1"
  },
  "cordovaPlugins": [
    "cordova-plugin-whitelist",
    "cordova-plugin-console",
    "cordova-plugin-statusbar",
    "cordova-plugin-device",
    "cordova-plugin-splashscreen",
    "ionic-plugin-keyboard"
  ],
  "cordovaPlatforms": [
    "ios",
    {
      "platform": "ios",
      "version": "",
      "locator": "ios"
    }
  ],
  "description": "helloWorld: An Ionic project"
}