I think it's a genetic mutation. But it's not a big deal because this way it can absorb more light.

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.

Does look like you have a phosphorus deficiency

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

It looks like heat stress. Raise your light a few inches, or dim it a little if you can.

It happens quite often with all the genetic modifications are cannabis has gone through.