Does kid always really change for "Sign in with Apple"?

I am doing Sign in with Apple for the first time.

My problem is, every time I parse `ASAuthorizationAppleIDCredential.identityToken` on jwt.io and on code, the `kid` is always changing. I don't know if this is really just the case or I am doing something wrong on my end. Maybe wrong instantiation of `ASAuthorizationAppleIDProvider`, `ASAuthorizationAppleIDRequest` or ASAuthorizationController`.

@available(iOS 13.0, *)
    private lazy var authorizationController: ASAuthorizationController = {
        let provider = ASAuthorizationAppleIDProvider()
        let request = provider.createRequest()
        request.requestedScopes = [.fullName, .email]
        let controller = ASAuthorizationController(authorizationRequests: [request])
        controller.delegate = self
        
        if let landingVC = self.delegate as? LandingViewController {
            controller.presentationContextProvider = landingVC
        }
        
        return controller
    }()

/// Sign in with Apple button was tapped.
func signInWithApple() {
        if #available(iOS 13.0, *) {
            authorizationController.performRequests()
        }
}

But, if it's expected to always change every time, my problem is, the parsed `kid` on my end sometimes does not match the `kid` parsed by our backend.

But, I just want to know if that's the expected behavior of kid? Thank you in advance!