I’ve just checked and my set is the same. I don’t think it’s anything to do with pipe speech – more likely the valve mechanism at the foot of those pipes. This would seem an obvious case for sample stretching – substituting a sample with better speech and transposing it. There seem to be two approaches to this sort of problem – in Hauptwerk the tradition is to sample an organ “warts and all” – only correcting a sample if the sound is very wrong; whereas companies like Allen aim for more even voicing throughout. I can see that minor variations in tone add life to a rank, but I often wish Hauptwerk's sample makers would tidy things up a bit more. As the Musette is one of the less used ranks I can only suggest that you omit it from your registrations.
I see that you’re from Mesa Arizona, so presumably you’re well acquainted with the wonderful Wurlitzer in the Organ Stop Pizza? I’d love to hear – and play – that organ; there’s nothing quite so huge in England! I particularly enjoy the way it was played by the late Charlie Balogh.