I’ve noticed some small brownish spots on the bottom leaves of my plants. I can’t tell if the issue is from Lighting or Nutrients. I currently use a Kind K3 Series2 XL300 LED Grow Light in a 72"x36" grow closet. Running the lights for 18 on 6 off. The Ph has been around 6.2-6.8. I also keep the humidity around 50-60%. The plants are about 2 weeks old and seem to be doing well besides this.
Might be a magnesium deficiency.
Don’t be in a rush to remove the leaves when you notice a problem.
Let’s say it’s a deficiency. The plant is drawing what it needs from those leaves. If you remove the leaves the plant will just take what it needs from the next set.
Watch the area to see if the problem increases. The bad stuff will never recover.
You didn’t say what or how much you’re feeding them. You might want to do a support ticket.