could be genetics.. could be that's the least amount of light in tent... could be some weird environmental thing -temp or rh in the corner... or genetics and any combination of any.. never really know when looking at a handful of plants with slightly different plethora of variables.
Never know.. they may be smaller but produce more grams per sq ft in the end, all other factors the same.
could rotate them to a better spot than the corner and see if that helps... but if it is genetics, you are probably hurting what you swap around more than helping the runty plant... no problem if photo/vege phase, but i wouldn't experiment with flower/autoflower context.. maximize best plants, keep the runts in the corners.