On 3 November 2019, a Boeing 787-8 descending towards Barcelona experienced an unanticipated airspeed increase and the unduly abrupt manual pitch response which resulted in a large and rapid oscillation in vertical acceleration during an otherwise smooth descent resulted in two serious injuries, one to a passenger and the other to one of the cabin crew. It appeared that the cause of the airspeed increase was an unexplained vertical mode reversion from VNAV SPD to VNAV PTH about 20 seconds prior to the upset caused by the response to it.