This is almost certainly due to overwatering..
Overwatering many times goes hand-in-hand with Nitrogen toxicity and/or pH issues. Both of which in the flowering stage can and a lot of times will cause the leaf "claw" although pH fluctuation usually results in sideways twisting leaves forming a "crab/lobster claw" I know I'm a little late on posting this but I wanted to bring this thread back up anyways.
I've had a few that have done the same thing. Brand new batches of soil (I amend and re-use soil usually) sometimes end up being a little high in N (for me at least)and the more sativa dominant phenos usually get this leaf curling, but not normally until the switch to 12/12. I've always just thought it was excess N during the switch to and beginning of flower.
For me it seems to take quite a bit of time to completely recover from N toxicity and it will definitely lengthen flowering. I even had a real picky bitch one time that wouldn't finish. Took it to 16.5 weeks and gave up (Keep in mind, this was a slightly Indica Dominant hybrid). It made decent bubble, but that's about it. Very racy, short lived, paranoid high.
I grow everything fully organic but haven't made the step to teas yet and maybe never will. I use the same recipe my grandfather taught my father and my father taught mepretty much my version of sub's "super soil" that I've been using for a long time. The only things I add are plain water every other watering, in between the plain water schedule I mix in blackstrap molasses, and top dress with alfalfa meal, fish emulsion and worm castings when needed. (Not always all three at the same time). It's excellent other than the sometimes excess levels of Nitrogen for outdoor gardens and with a few changes can meet the needs of any plant. Outdoors I usually bury fish 1-2 feet down. The corn, beans, and squash all love it
After seeing those pics I'm on the fence now. Not sure if its a mutation /deformity or if its due to high N soil.