@clovergarden this is normal, it has to do with the formation of bud, when it grows it ends up squeezing and twisting the leaf, it usually happens even more often with automatic plants. they look great. good luck in flowering mate
@clovergarden I dont see any burnt leaf tips so I doubt its a nitrogen overdose i'd heve to say its because that part of the plant is closest to the lights which is a higher temp than say lower
down on the plant