When Deckard is talking to the Egyptian snake vendor, you can see through the glass that each characters dialogue does not match their mouth movements. This is true in all versions of the film, except the Workprint. Even in 2007 "Final Cut", the obviousness of the error has been reduced, but if you look closely, you can still see that the audio doesn't quite match the visual.

Being Tyrell a so-called "god of biomechanics", and having manufactured cutting-edge replicants for many years, even decades, it seems impossible that he knows little about the Voigt-Kampff test and has never seen one, as he asks Deckard during Rachel's test.