Null Value in getStringExtra()

Question

I am trying to build a notification service using the firebase Messaging Service. Problem is When I am clicking the notification It takes me to the correct intent but my App bar title is not updating properly. I am passing the username in the intent but in getExtra() of the Intent, it returns null. I am getting the correct userId but not getting correct name. My code for notification builder looks like this:

   NotificationCompat.Builder mBuilder =
            new NotificationCompat.Builder(this, CHANNEL_ID)
                    .setSmallIcon(R.drawable.chitchat_icon)
                    .setContentTitle(notification_title)
                    .setAutoCancel(true)
                    .setContentText(notification_message);


    Intent resultIntent = new Intent(click_action);
    resultIntent.putExtra("user_id", user_id);
    resultIntent.putExtra("user_name",user_name);
    TaskStackBuilder stackBuilder = TaskStackBuilder.create(this);
    stackBuilder.addNextIntentWithParentStack(resultIntent);
    stackBuilder.addParentStack(MainActivity.class);

    PendingIntent resultPendingIntent =
            stackBuilder.getPendingIntent(
                    0,
                    PendingIntent.FLAG_UPDATE_CURRENT
            );

    mBuilder.setContentIntent(resultPendingIntent);

I am getting Intent Extra and setting it as the title for the action bar:

   //change in postion
        mChatUser = getIntent().getStringExtra("user_id");
        String userName = getIntent().getStringExtra("user_name");
...
 mTitleView.setText(userName);

My firebase js function to generate notification looks like this:

 const fromUser = admin.database().ref(`/message_notifications/${user_id}/${notification_id}`).once('value');
   return fromUser.then(fromUserResult => {
   const from_user_id = fromUserResult.val().from;
   const message = fromUserResult.val().body;

    console.log('You have new  notification from :  ', from_user_id);

    const userQuery = admin.database().ref(`/Users/${from_user_id}/name`).once('value');
    return userQuery.then(userResult => {
    const userName = userResult.val();

    const deviceToken = admin.database().ref('/Users/'+ user_id +'/device_token').once('value');
    return deviceToken.then(result => {

    const token_id = result.val();

    const payload = {
     notification: {
      title: userName,
      body: message,
      icon: "default",
      click_action : "com.example.chitchat_TARGET_MESSAGE_NOTIFICATION"
     },
     data : {
     user_id : from_user_id,
     user_name: userName
     }
    };
}

Can anyone help me how to solve this problem? Can't Locate the issue. Thanks.

Update:

I also want to share that it works fine if there are two different devices but if I log in and send notification logout and receive notification it can't retrieve username.