Ionic 3 with firebase authentication... app reloading two times on build

Appflow
1

When I implemented the Lazy Load in my app with firebase, always when I build the application, it reloaded two times when using this code in app.components:

const authObserver = this.fire.authState.subscribe(
    users => {
      if (users) {
        this.rootPage = MainPage;
        this.userService.carregarPerfil();
        authObserver.unsubscribe();
      } else {
        this.rootPage = FirstRunPage;
        authObserver.unsubscribe();
      }
    }
  );

What can I do to stop happening this?