Two Liva Nova centrifugal head disposables that were noticed to make an unusual sound during priming. The first one (07/01/2020) was observed to wobble (video footage sent to company). The second disposable (24/01/2020) was not noticed to wobble but there was an audible hum that replacement with a new centrifugal head removed. In both cases the issue was noticed during priming and the disposable was able to produce flow but the suspected flaw was felt to be potentially dangerous.