Leaves are look sick.

Its hard to tell if its a nutrient problem. What kind of soil are you using? Are you adding nutrients? I can see you have a little bit of nutrient burn( tips of leaves are brown ). On day 22/23 that one leaf looks like it has a rough time. And it looks like this is the same leaf. So this could be the result of abrasion damage and nothing to worry about. The leaves look very green which is a sign of to much nitrogen. But I don't see the "Claw"( tips bend down) so it could be just the camera/lighting. She is looking good to me. Lower leaves that are not receiving light will age off but this is usually only looking color first. Its the brown spots I can see your concerned about. Now after inspecting closer Yes I believe its just abrasion damage and a lack of light to the lower canopy, Nothing to be worried about. From your picture labeld "Day29 /look closely on first set of leaves/" the bottom leaf tip that is yellow is normal because it is not receiving light. and the left leaf is in the same location that got beaten up on day 22/23. Happy Growing