Hello my friend, this is just a color mutation that you find very often on cannabis plants. This is not a problem or deficiency. So no worries and enjoy this grow buddy! 💚
Most likely just some odd leaf pigmentation..
there are pests called 'leaf tunnelers' ... but it would be very obvious very quickly if it spreads. you'd be able to find evidence of them on your plant.
no spread = no problem. normal stuff