They didn't identify the new case in November. There is a report of a case that was retrospectively dated to mid-November, by searching through patient records

They didn't identify the new case in November. There is a report of a case that was retrospectively dated to mid-November, by searching through patient records and probably by re-testing samples. But that retrospective analysis was done months later. The virus was not identified until the end of December, which is more than a month after the case in mid-November.