COCO COIR Holes on leaves. Help please!

[Tjorp]

Is that dangerous? Bugs or some deficiensy?!?

[Tersky]

Looks like some kind of pest. Check the leaves top and bottom with a 30x magnifying glass as some pests are too small to see with naked eye. It looks more like caterpillar or inchworm to me but i could be something else. Check this link for diagnosing and fixing your plant. https://www.growweedeasy.com/cannabis-symptoms-pictures

[BakedMoose]

the second picture almost looks like it's a friction issue. Were you tying those leaves or anything in their vicinity down? If you weren't, then I'd have to agree with a pest of some kind.