Leaves can curl for a variety of reasons, ph problems, extreme humidity high or low, light and heat stress, as well as overwatering. I see you water each day, they may not need that, perhaps every other day, typically if top soil is dry up to your 1st or 2nd knuckle. I also see your light is at 18 inches, I think many led companies recommend about 24inches at this stage, but that could cause the light and heat stress. The plants look pretty good to me and I think this just a temporary problem with a few minor changes. However 55% isnt a bad humidity for this stage. I think give her a healthy flush, move the light, possibly add an additional small fan and things should take off again. Best of luck with the tweaking of circumstances. Happy growing.