Yes, I recently bought The Three myself and noticed the static sound after a while. I was worried it was a manufacturing error or a damage to the speaker, but realizing this is a production thing.
Its probably too low for most people to hear it, but Im sensitive to that stuff. It sucks cause when you first notice it, its hard to un-notice it.
At least you cant notice it when playing music, but for being semi-expensive speakers from a brand with high reputation its disappointing.