[@nativescript/google-signin] - Signin does returns undefined for serverAuthCode

While implementing the pacakge i see that in the response the serverAuthCode comes as undefined. I do get accessToken and the idToken. Because of the way our backend works we need the serverAuthCode . Is it know to not be working or might i be doing something wrong?
i'm configuring it like this
GoogleSignin.configure({
signInOptions: 'default',
clientId: environment.google_login_ios_client_id,
serverClientId: environment.google_login_server_client_id,
});
in the main.ts of the app before starting the app up
Using the versions:

• "@nativescript/google-signin": "^2.1.1",
• "@nativescript/core": "~8.9.2",

Reproduce the sign-in flow from the configuration shown in main.ts using @nativescript/google-signin 2.1.1, and inspect the package's handling of serverClientId and serverAuthCode. Compare the response with the reported accessToken and idToken values; done means determining whether serverAuthCode should be returned or documenting the limitation and required configuration.