I have owned 2 Curt hitches. Both Q20, one roller base and one stationary. Here’s why they suck:
The roller is doing what the OP describes because of the slop between the base and rails. Yes the fix is the pads but you need all four, and yes you will have to beat the pins in with a hammer and I used an angled vice grip to give me a flat surface to hit. You will also curse, sweat, and likely bleed when you need to beat them out.
The fixed base model cracks the rails, sinking deeper into them creating a increasing slop condition. This is due to poor design, and possibly inferior steel quality of the rails. I will attempt to provide pics here, but the issue is the tab design. It concentrates the pin weight onto tiny points adjacent to the slots. Curt replaced my rails but I still spent $300 getting them reinstalled. First trip after new rails went in-almost exclusively on decent interstate (about 1000 miles)-and rails are cracked again. All 4 slots. Perhaps the pucks are better but I would advise anyone considering a Curt to keep shopping.
Curt has been a huge disappointment but the selection of hitches rated north of 20k is slim so I made a second attempt with the non-slider model.

