AES-256 cipher is already quantum safe (Shores Algorithm does not apply to AES-256) but the quantum achilles heal of TLS communications is the asymmetric key exchange (often RSA or Elliptic Curve) that establishes the shared key used by the AES-256 payload encryption side of TLS. The concern is that any TLS handshake and data traffic recorded today could be later decrypted offline when quantum computers catch up. Lengthening the RSA key size kicks the can down the road, but ultimately TLS cipher suites will need to add a quantum safe suite of key exchange algorithms.