Not sure what’s wrong

Might be your light is too strong for this stage.

Honestly if it's week 2 and your plants are that big you are doing something right, looking healthy, big fat leaves. Plants maybe starting to lime green a little but that could just be lighting in the photo, no signs of any real problem, could be tacoing by looks of it, but very early, you yourself would have a idea of how hot it's getting in there, Taco curling is heat+drought stress -- the tree is trying to make the leaf surface area smaller to reduce sun heating. Aside from intense sun or being near a heat source like a dark hot surface, it can be caused by inadequate water uptake on hot days. Given your growth is fast, possible she is running out of water for cooling at some point near the end of the daylight cycle. Things go taco Loco when water gets low. Get yourself a ec metre. Use it to tell you when it's time to water. Pop in dry soil if ec low, water saturate soil, wait 20 min take ec again, if still low fertilize, if high enough leave until next watering. Ec is life currency of soil if there is no ec there is no photosynthesis, no photosynthesis no transpiration, no transpiration then water sits in pot at behest of evaporation and evaporation alone. Evapotranspiration is sum of both. Right now she is using more nutrients than she is receiving based on high demand from light intensity. Either lower dli intensity slightly or up dosage of fertlizer, and make sure that pot is drying up near end of day. Gluck.

I agree that light is probably a little much for her. You're running a little over 300 Watts in that 2x4; which is great for flower (and even veg) but everything else needs to be dialed in nice for you to crank that light up and place it low. I run overpowered lights in all my tents, I usually only crank them up for real after pre-flower is done and I have done a major defoliation and they have recovered. I might turn them down the last week or two and alter photoperiod to 18 on, depending on how she is behaving. Sometimes I might change to an 8 hour photoperiod the last few weeks and really crank it/put it low. Also agree with the pH. That new growth could be normal, honestly. I've had some plants that like to unfurl leaves like that, sometimes it was a stressed plant that led to intersex flowers, sometimes it was just the cultivar.

Aight mate listen, dat ain’t no big deal but yeah somethin’s off. Leaf tips curlin down, lil yellowin… lookin like early sign of light stress or pH swing. U runnin dat Mars FC4000, 35cm distance at 50%? In veg still? Too close bro, dat light cookin her like she sunbathin on Mercury. Pull it back to 45–50cm for now, she ain’t askin for that much juice yet. pH at 5.6 a lil low for soil bro, aim closer to 6.2–6.5 or she gon’ start bitchin soon. Roots need buffet, not acid rain. Rest look fine tho. Don’t go full panic mode, adjust light height, check run-off pH if u can. She’ll bounce back, just don’t baby her too much or overwater now. She tough but not bulletproof. Stay grindin,

For me it looks not fine but okay :-) especially for early veg. The slight droop and minor leaf curl could just be a reaction to watering or environmental changes (heat, light)– nothing to worry about. Leaves often adjust themselves during growth – as long as the color stays healthy and new growth looks good, you’re on track. No sign of any real problem here – just keep steady with your care and watch the plant settle in. Anyway compared to others I am rather harsh to the ladys and don't care about slight problems😇