Bigdog, I have confirmed(I think) one thing that someone did actually mention and that was not being consistent with watering. I have found that even when I think I'm over watering I'm really not and when I just let the water run for a long time actually watering properly it sort of shocks the plant and the leaves get a super boost from all the water/food. This makes them grow to fast and curl.
The only other thing that make any sense is what Joereal said about our California climate being too dry, but you are not here.
Right now I have a plant growing curly leaves with the other plants around it growing normal leaves.
One thing I can tell you for sure is that curly leaves make no difference in how fast they grow, and they will still fruit even while growing curly leaves.
