ios – ASAuthorizationControllerDelegate always returns .canceled for Face ID passcode fallback and failed attempts

I’m implementing Sign in with Apple / Passkeys using ASAuthorizationControllerDelegate and handling errors via:

   func authorizationController(
    controller: ASAuthorizationController,
    didCompleteWithError error: Error
) {
    guard let authError = error as? ASAuthorizationError else {
        print("Unknown error:", error)
        return
    }

    switch authError.code {
    case .canceled:
        print("User canceled authentication")

    case .failed:
        print("Authorization failed (generic)")

    case .invalidResponse:
        print("Invalid response from Apple")

    case .notHandled:
        print("Authorization not handled")

    case .unknown:
        print("Unknown authorization error")

    @unknown default:
        print("Future unknown error")
    }
}

However, I’m consistently seeing .canceled in all of the following situations:
• User taps the ❌ button → .canceled (expected)
• User cancels during Face ID → .canceled
• Face ID fails and falls back to device passcode
• User enters the wrong passcode → still .canceled

I never receive .failed for passcode failures or biometric fallback failures — only .canceled.

Questions

1. Is this the expected behavior for ASAuthorizationController?
2. Why does a failed passcode attempt result in .canceled instead of .failed?
3. Is there any supported way to differentiate user cancellation vs authentication failure (Face ID / passcode) using this API?
4. When should .failed actually be expected to occur?

ASAuthorizationError.Code