Can't re-log (autorelog) user to Nativescript Firebase App on iOS

Question

I'm having problems re-logging the user previously logged in with Facebook or Google Sign In on my Nativescript iOS App. It works good with an email/password re-authentication on iOS.

It seems that the function

     firebase.init({
        persist:true,
        onAuthStateChanged: (data: any) => {
            console.log(JSON.stringify(data))
            if (data.loggedIn) {
                AuthService.tokenUid = data.user.uid;
                // this.routerExtensions.navigate(["/splash"])
            }
            else {
                AuthService.tokenUid = ''
            }
        },
        iOSEmulatorFlush: true
    }).then(
      () => {
        console.log("firebase.init done");
      },
      error => {
        console.log(`firebase.init error: ${error}`);
      }
    );

return {"loggedIn":false,"user":null} when the user re-launch the app after closing it. It seems that the plugin nativescript/firebase (EddyVerbruggen / nativescript-plugin-firebase) might have a problem with the authentication on iOS. There is no problem with Android.