I have a 2019 can am defender that was doing the exact same thing. I tried tighting the sway bar in the back and greasing everything like all the other tread suggested was the problem and nothing worked still popping when hitting bumps. Finally after 2 days of looking for it I finally found the problem and it was the 2 bolts on the roll cage where it comes together on the lower left side by driver seat was a little loose. Not hand loose but enough to where when I hit a bump it would cling. Tighten those up and stop the clumping noise.
