The Huawei Mate 20 has been spotted in the wild by a keen observer during IFA in Berlin. The device features a distinctive square rear camera arrangement, so the photo looks legitimate. That said, it is not especially surprising a Huawei representative would have the device in hand given its official launch in London just over two weeks away.
https://www.notebookcheck.net/Huawei-Mate-20-spotted-in-the-wild-set-for-October-16-official-reveal.328588.0.html