FirebaseUI authUI callback not being called upon email/pass sign up

I'm using FirebaseUI to authenticate users but my authUI(_ authUI: FUIAuth, didSignInWith authDataResult... callback is not being called upon email/password user sign up (NB: sign up, not sign in). All works fine for Google and FB signups, and for subsequent sign ins via pass/FB/Google; only email/pass sign ups are causing me grief. Here's the code:

struct MyLoginViewController: UIViewControllerRepresentable {
    
    func makeCoordinator() -> MyLoginViewController.Coordinator {
        Coordinator(self)
    }
    
    func makeUIViewController(context: Context) -> UIViewController {
        let authUI = FUIAuth.defaultAuthUI()
        let providers: [FUIAuthProvider] = [
            FUIGoogleAuth(),
            FUIFacebookAuth(),
            FUIEmailAuth(),
        ]
        authUI?.providers = providers
        authUI?.delegate = context.coordinator
        
        let authViewController = authUI?.authViewController()  
        return authViewController!
    }
    
    func updateUIViewController(_ uiViewController: UIViewController, context: Context) {
        //
    }
    
    class Coordinator: NSObject, FUIAuthDelegate {
        var parent: MyLoginViewController
        
        init(_ myLoginViewController: MyLoginViewController) {
            self.parent = myLoginViewController
        }
        // MARK: FUIAuthDelegate
        func authUI(_ authUI: FUIAuth, didSignInWith authDataResult: AuthDataResult?, error: Error?) {
            if let error = error {
                assertionFailure("Error signing in: \(error.localizedDescription)")
            }
        }
        
        func authUI(_ authUI: FUIAuth, didFinish operation: FUIAccountSettingsOperationType, error: Error?) {
            if let error = error {
                assertionFailure("Error: \(error.localizedDescription)")
            }
        }
    }

Thanks