Reverse taco curl

So I just put the ladies into flower on Monday and a few of them are doing the "reverse taco curl?" Heat and humidity are good about 75 degrees F and humidity at about 35%. I have checked the pH and it is still okay. Runoff at about 6.8, a bit high, but I ran about 10 gallons through it trying to lower it, but it didn't seem to help. I am using FF Ocean Forest Blend and it seems hard to correct the pH. Anyone have issues like this, I know FF is suposed to be pH buffered, is this why? But anyways, they are getting light feedings of Bloom nutes and there are no signs of burn, but I can't figure out what might be causing the taco curls and I would like to get it corrected before it really becomes a problem, since right now it is only a few leaves on each affected plant. Thanks for any help in advance!

I've noticed that curl when my ladies are rootbound? how big are your plants and what size pots?

Over fertilizing, and over watering can cause curling. Whats the ppm for the nutes?

I don't think they are rootbound, since I just transplanted them on Monday into 5 gal. pots for the flower. The nute feedings have been reeeaaal light. We are using the early growth recomendation from Flora Nova, it is about 450ppm according to the instructions on the container. We also have other plants of the same strain that are not taco-ing under the same feeding schedule. Overwatering could be possible, although I only tend to water when they feel and look dry... Oh and the plants are currently about 1 1/2 to 2 feet.

6.8 ph is good for soil
no pics?
down curl probly from root bound since u barley transplanted unless may be sometimes my ladies look sad if im rough with transplants

but without the form and pics thats the best i can say