FCM Event instances are not clearing while removing the component from react-native-router-flux Actions route stack

I am Using **FCM.getInitialNotification().then((notif) => this.getInitialNotificationFunction(notif));
this.notificationListener = FCM.on(FCMEvent.Notification, async (notif) => function(Notif)**
Both FCM Methods are executing multiple time.

**_Issue Explanation :_** I Closed My App By Clicking Device Hardware Back Button and Again I opened App By Clicking On The App Logo From Home Screen Of Device. here if I am Getting A FCM Notification Both Methods( FCM Method Mentioned Above) Are Executing Multiple TImes. If I close The App 3 Times Then FCM methods Are Executing 3 Times, If I Do This Process 4 times Then Methos Executes 4 Times.

And I Am Using **react-native-router-flux** For Navigation. When User Clicks Hardware Back Button I am Removing The All App Components(Screens) From react-native-router-flux Actions Stack(It Means When User Open The App, App Starts From The Splash Screen Component.)
@evollu Help Me On This.

### Environment
1. Application Target Platform:
**Android OS**

2. Development Operating System:
**React-Native With Redux**

4. React Native version:
**react-native-cli: 2.0.1
react-native: 0.50.3**

5. RNFirebase Version:
**"react-native-fcm": "^11.2.0",**