I use to see this quite a bit when using B52 early on along with sensi grow a/b and voo doo. I found the b52 to have to high an npk ratio and was curling not all but some of the leaves. Since learning that b Vitamins do nothing to enhance growth so I have dropped b52 and started with Nirvana earlier. Point being when I made the change and lowered the npk ratio all around I have not noticed any significant leaf curl. It will grow through it you will have some monsters. You should look up the King gangamoto he kills with dutch pro nutrients check his schedule out his plants make mine look tiny. Are you feeding full strength once a week? Then water the rest? I really only have truly great growth with Advanced nutrients which is PH perfect the line up I use. Dutch pro you will need a ec and ph monitor and maybe have to correct your PH up or down with dutch pro but it is still one of the best nutrients out there. Just to let you know I have had curl like that and they have turned into monsters. Is more the top leafs showing the curl then the bottom leaves if so you in my mind are growing through the deficiency then. Some Phenos are more prone to it at a young age. But I feed from day ten on every watering has food at 1 mill a liter with sensi a/b one mill of voo doo Until about day fifteen or so they get between 500 mills to a liter of nutrients by day day 20 they should all be getting close to a liter in a 24 hour period. What is your growing medium and ambient temps? And where is your relative humidity at it must be below 50 % to achieve maximum growth. And make sure you have wicked air exchange bro. Here is a royal queen northern lights auto killer weed Royal Queen has there ducks in a row for sure broView attachment 553914
That Sensi ph perfect is nice stuff. I have some sensi bloom a and b connoisseur that my friend gave me which is supposed to be pretty good. I use Green Planet GP3 it is a new three part microbe,grow and bloom. Before that I used medi grow and that whole line up from GP. Royal Queen Seeds have some of the best genetics I think,very high quality breeder. Got love it when a plant falls over from it's own weight.