hey there Val, i'm quite sure this isnt due to light stress. that's because you're not using a big kind of light. what it looks like to me , is a pH issue, probably due to a sort of slight overwatering issue. it's easy for this to happen , especially at this stage. You can tell from the splotchy sort of discoloration on the leafs and the discoloration on the tips of the leafs. it means the nutrients from the soil are "too available" to the plant . you need to make extra sure that you're following a strict wet dry cycle , you can even try misting these first few weeks , after all the roots arent really that big at this point, just make sure all the water droplets dont collect on the leafs and lead to magnification and light issues. Hope this helps ! 🚀