title: Current user set to null even though is logged in
body: <p>I have created Auth Service</p>
  
  <pre><code>import { Injectable } from '@angular/core';
  import { AngularFireAuth } from '@angular/fire/auth';
  import { User } from 'firebase';
  
  
  @Injectable({
    providedIn: 'root'
  })
  export class AuthService {
    user: User;
  
    constructor(public afAuth: AngularFireAuth) {
      this.afAuth.authState.subscribe(user =&gt; {
        if (user) {
          this.user = user;
          localStorage.setItem('user', JSON.stringify(this.user));
        } else {
          localStorage.setItem('user', null);
        }
      });
    }
  
    async register(email: string, password: string, displayName: string) {
      await this.afAuth.auth.createUserWithEmailAndPassword(email, password);
  
      await this.user.updateProfile({ displayName });
  
      this.user.sendEmailVerification();
  
      return this.user.uid;
    }
  </code></pre>
  
  <p>after user is successfully registered i can access user property and call updateProfile function.</p>
  
  <p>But i want to use this service also for updating profile information like: email or phone,
  but whenever i do that i am getting user set to null.</p>