Leaves clawing, but not droopy, with pics

Here is a White widow 1 month into flowering. I can't figure out why the leaves are clawing ? I'm running 2 600w lights, FFOF soil, R/O water with fox farm trio nutes. Notice WW is a fast drinker and sometimes she become a little underwatered. Not here though she drank about 3 hours prior to this pic. Light is set for 18hrs but 3 flowering plants are removed at 12 hrs and oters are going to veg for 10 more days

What do you guys think is causing this?

Start by checking PH. esp with RO water.

How far do you think the ph could be off? Id figure after running through the medium the ph would drop about .4-.6 and be right in the ball park of where I need it to be. I could be wrong though

its probably a combination of the ff soil and the nutes. ff is hot to begin with...claw results from too much n. you have a slight case, not a bad case of claw. i would try flushing all that n out of your mix. and feed less n to reverse the onset of major claw which is a problem that can't be reversed.

I was going to second that its nitrogen toxicity. It's either that or a ph problem. I used FF back in the day, personally, I would never use it again..

Too much N

they look like they are coming along nicely, I don't think there is too much wrong with them, heres a tutorial pic I got showing leaf clawing, which like most above confirm, suggests nitrogen overfeeding--this pic is way worse than yours