My ZW has been this way ever since I got it. It has the new metal brackets and the right handle was very loose and the pot would skip teeth. I fixed it myself with a 3D printed part I designed and a u shaped bearing to take the slop out of the handles. It works like a charm now. What I found is I had to make the new bracket a little shorter to ensure good gear engagement. My suspicion is that right side of the molded base is somehow a little off and the gears just don't mesh right. I have never had any issue with the left handle.
I made a video on what I did. https://youtu.be/Jl6v_zffsGQ