While a Connect awaits its Accept, only an Accept the client honours retires it. An Ack that names the Connect (a server's reply to a repeat or a stale copy) no longer wedges the client with nothing to resend. The Connect payload lives on the session, so a fresh attempt can always be built. The fresh attempt uses the abandoned sequence plus the receive window less one (serial), so a late copy of the abandoned Connect stays inside the new one's stale window; only a session's first Connect draws at random.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>