Retaining Firebase auth credentials after redirect

I'm using Firebase authentication (react-firebaseui with Google & Facebook sign-in) in a single page web app in which the user also needs to authenticate against other systems using OAuth redirect flow to gain access to 3rd party APIs.

My problem is that Firebase authentication credentials are lost after the user authenticates to these 3rd party systems through OAuth (redirect flow).

How can I retain the Firebase authentication session and regain Firebase credentials after the redirect?

I've tried persisting the authentication credentials and then invoking signInAndRetrieveDataWithCredential after the redirect, but this doesn't appear to work.