If it's just those bottom leaves (which it looks like) that's likely just from them resting on the damp soil at some point, so nothing to worry about... It's possible you are over-watering a bit as well though which can cause the droopy leaves.
Also unless you're having trouble keeping your temps up it's best to run a 20/4 light schedule, the general consensus is that its best to still have some dark period with autos.