What could that be? There are no insects or anything in the tent. I use half the recommended amount of nutrients, and the light is 70cm away (can't go higher, the tent is too small).
Hello,
It looks most like it might be an attack of the fingers? I'm really bad about checking over my plant or watering and accidentally nicking a leaf with a nail or sometimes a pair of sheers. Especially if you're sure there's no bugs.