I got my 2014 535CGT secondhand, so I just assumed the gauges vibrated excessively because it's a thumper and that's just how that goes. Fast forward to last week and suddenly the vibration changed, so I decided to feel around for the mounting bolts for the bracket, thinking maybe they were loose. I discovered that the left side of the bracket had cracked and completely broken off, and upon further inspection found the right side was also cracked and well on it's way to breaking off. After attempting to make my own out of sheet metal, I ended up making some small "splints" to bridge the cracks, held in place by the original mounting bolts and one 6mm nut & bolt through the unbroken portion of the bracket on each side. A few days of riding to work and the gauges are more stable than ever, so it appears to have been a success.
(I know Hitchcock's has replacement brackets, but the shipping to the States is as much as the bracket so I decided to take a swing at repairing it.)