Seedling, light green edges of leaves

probably related to odd watering required for a big pot and tiny plant. if this is an auto, don't fall for the 'don't transplant autos' nonsense. avoiding this exact situation is why. water a slightly larger diameter than the leaves, but make sure it soaks all the way down, otherwise you are likely causing all sorts of weird drying patterns in the root zone. what might be a safe, low charge of nutes in the substrate can turn into high concentration as the water evaporates. you want it drying up top first, not somewhere around the roots. stick with it, water a bit more thoroughly and deeply and i'm sure it'll be fine in a few days. it's way too early to have leaf symptoms.