Not light correspondence.Does the left right thing correspond to where your lights are?
Maybe your circulation fan?
Some other thing like that, an obvious difference in environment.
With leaf cupping and no obvious burn, I usually think heat and humidity.
Maybe genetics yes, many of them do it whilst many do it, perhaps some are more reslilient.It's probably just a different pheno than the other one, or your fan is hitting it in the ricochet of your wall or whatever and causing it to protect itself.