The validity is up to the service, as described in https://datatracker.ietf.org/doc/html/rfc6238#section-5.2 https://datatracker.ietf.org/doc/html/rfc6238#secti

The validity is up to the service, as described in https://datatracker.ietf.org/doc/html/rfc6238#section-5.2 https://datatracker.ietf.org/doc/html/rfc6238#section-5.2 Because of clock skew and latency, a service might choose to allow the previous and/or next code as being acceptable.