Bet either wringer rollers are just slightly stuck, and or seller just didn't know how they operate.
Bit of hosing down with water and keeping rollers wet for a bit likely would cure any stickiness. OTOH if they've developed flat spots good luck finding replacements.
In old days it was recommended to gently wipe down rubber wringer rollers with bit of kerosene (a substance that seemed to be in all homes back in day, don't ask one why), to clean and deal with slight flat spots. Rollers then had to be washed down thoroughly with soap/detergent and water to remove all traces of petrol.