Curling of leaves on young Chemdawg x Blueberry Kush?

So my girl got 3 free seeds last time she was helping her friend harvest his crop. I was told her friend does his own cross-pollinating, and the parents of the seeds were an F1 Chemdawg and an F1 Blueberry Kush. The seeds were a tad old (about 3 months) but stored well I suppose, as all 3 germinated. They're now a few weeks old and doing well. However, two of these little plants are starting to have some goofy curling of the leaves (as pictured). What is causing this? I've read that straight Blueberry tend to have curled leaves when their young, but they straighten out before reaching maturity. Is this true? Or am I doing something wrong?

They're currently on a 24-hour light cycle and being fed a 7-7-7 growth fertilizer at half strength (I just started feeding them a few days ago, the curling was prior to feeding).

Much thanks, they seem quite healthy despite the curling. Also, the pictures look like the leaves may be a bit yellow on the edges and tips, but that's the picture quality and lighting. They aren't yellowed in person.

i tend to think it's just genetics.. pure bb can be a real night mare to grow from all i've read about it..

i also don't think it has anything to do with lights or food or w/e.. if it was too far from the lights, it would stretch trying to get closer to it, not curl like what you've got going on...

i wouldn't sweat it. some plants are freaks.. a lot of times the freaks are some of the best smoking of the lot.. so long as they otherwise look healthy and are growing ok, i'd not worry too much about it..