Thanks for the suggestion. I gave this a try but the blocks still vibrate, though a lot less, back and forth rather than move consistently from point a to point b. Still stuck.
Update!
Figured it out. Turns out the Random Effector was applied to the Fracture and the top level Clone, but not the bottom level Clone. When I copied it into it as well, everything worked fine, the columns broke up into individual elements using just the Random mode rather than noise.