When a refresh_token is used to get a new access_token, is the old access token automatically invalidated/revoked?

When a refresh_token is used to get a new access_token, is the old access token automatically invalidated/revoked?

No, it will not, and the assumption would be that the first access token has expired (or is about to) if you are making a refresh request. If its not expired yet, you could always manually revoke it.