Plato high pitched sound?

I just got my Plato yesterday, which I absolutely love so far, however I have noticed something that seems a little strange and was wondering if it's just me. While firing my Plato the device makes a super high pitched sound, like a very electronic squeal. When I say it's high pitch I mean barely perceptible, something that most adults likely wont even be able to hear at all.

It's not a deal breaker or anything, just wondering if anyone else has had the same issue. Otherwise I absolutely love this little guy. Great replacement for my NEBOX.