Yes, and let me clarify here. I don't think ALL of the stern cabins vibrated on our cruise either. But I couldn't visit all cabins in that area, of course. There were fellow guests with cabins on or near the stern who said they had little or no vibration, and I believe them. Vibrations are very difficult to diagnose, and even more difficult to fix. One suite can have a problem, and the one next to it can have no problem. Then, the area subject to vibration can actually change, from cruise to cruise. And it is not subjective.
All I know for sure is that our suite (784) had excessive vibration and shaking on our cruise, and ditto for the suite on deck 9 above us. If anyone can access any of my reviews of the Navigator (when its vibration was a "hot topic"), they will see that we are very vibration-tolerant. And I know that there was some vibration (though not always excessive) in the halls near the stern, and aft of the laundry room areas on our Voyager cruise. So all I can say is that, for our future Voyager cruises, we will book a suite forward of the laundry room areas. And I too could find no vibration anywhere else on the ship. In fact, other areas were notably vibration-free!
Hope this helps,
Richard :) :) :)