It's probably heat stress as others in the thread have noted. I've seen it as well, but wouldn't worry too much about it.
I don't think it will influence yield in a significant way.
Its just a gentic mutation
There's a breeder that sells strains and all their strains the fan leaves come out crazy.
Your type of pheno they'd love to mix that into their gentics.
Your bud will be normal..probably have extra photosynthetic reaction