Not sure what “rare” is but getting a new transducer that does not work is not unheard of. Although there are not many components inside of a transducer and these are typically potted in an epoxy; they can still fail. Sometimes this is due to handling and sometimes something inside just fails. We of course test each one after they are made but they can still go bad afterwards. There are ceramic elements inside of these so a little care must be taken to not drop them on a hard surface as we have seen them fail due to this.