Hello Dj it's pretty hard to diagnose just with a picture... I see water drops on a couple leaves, if you spray a plant with the lights on it can burn the leaves because the droplets act like a magnifying glass... also the soil seems to have quite a bit of wood in it and this can create hot spots in it, as organic material decomposes it creates nutrient enriched soil if this is not balanced with other amendments it can burn your plants as the roots grow though the hot spots
Hope this helps you
Cyrus