I'd say maybe pH is messing up your leaves...but I've also had plants with "perfect" pH make an occasional twisted leaf. Are you sure your water pH is good? They may have wet feet in a pot that big, they should grow out of that. Get your light closer...4ft is too far. They're looking good...just a few minor changes.
It's also along with Mg Def the standard canned answer on almost every MJ forum I have ever been to. Little plant/big pot is probably the problem I agree.