After your post, I observed how the water was coming out of the sprayhead on my Brazen Plus 3.0 (the latest version).
Indeed, the water was only coming out of the center 8 holes, so I reasoned that it could have limescale buildup (I use a Zero Water, which removes all minerals, but I remineralize using Third Wave Water packets).
I de-scaled using Urnex Dezcal solution, and the problem seems to have been rectified.
I was a bit surprised that it scaled up the showerhead after only a month, but then, the Third Wave Water is fairly high TDS (~ 120-130 PPM), at least, when you use their suggested ratio of 1 packet to 1 gallon of water. Which I had been doing.
I decided to start cutting in half the amount I use, which will take TDS down to around 60-70 PPM.
We’ll see how it does.
Incidentally, for anyone reading this, the Technivorm Moccamasters are on sale on Amazon right now for 30% off. Dang good deal. Over $100 off.