Check the back to back size and of the rim against the other side, you may find one is slightly larger than the other. Replace the badly fitting one or use packing at the screw to tighten the rim down against the retaining lug at the top.

Ian
2011 Plus 4
Wild Mogs Reims 2019, Goodwood 2018, Isle of Man 2017, Carried on to Caramulo" 2016