I had a simular pattern on my leaves in my hydro grow: even cuts across leaves just here and there, not massive. I never found out what it was but I asked my cat and she said "No Comprendo" I think she had something to do with it................. I never found a flying monster bug anywhere.
hey man check your plants because i had a similar issue but with holes and comps on tips of plants and for some reason a tiny caterpillar was chewing away at my little autoflower so check and make sure turn the leafs over
Unless it something you are seeing on other leaves I wouldn't sweat it. Looks like some type of mechanical injury as the leaf was developing but it does not look any type of insect damage. At any rate this one little vegetative-stage leaf won't matter in the long run. Just keep a careful eye on the others.
im having the same problem on like one or two leaves!.I think it's from over foliage praying causes the leaf to split open from drying out during the light period.That's my opininion and that's the only thing i could think of because i don't have any pest problems.