If the leaves are curled in on themselves, it is a Physiological disorder called Leaf Roll. The roots can’t take in enough moisture to support the leaves, so the leaves make themselves smaller. Causes include excessive moisture, too much nitrogen, severe pruning, root damage or transplant shock. Avoid high nitrogen fertilize. Keep the soil evenly moist. Those leaves do not flatten again, but new leaves will look normal.
Leaf curl has little effect on production.