All this chat and not one has taked about the ph of the water that you use. what ph is the water you use anyway? They have talked about temp, most of the time the temp is what will do that to your leaves, but not all. I have a bubba kush strain indoor that does that if the ph goes over 6.8 but all of the other strains in the room are fine, the temps in the room never go over 80. Most of the time it is a ph problem they get what we call twisty leaf. Yet i have the same strain cloned plants that are outside in temperatures well over 100 that get 8.0 water and don't have any leaf curl. I think ya got dooped on ya bean. Even with clones there are stronger plants than others from the same mother cloned at the very same time. Personal opinion on your problem is genetics.... you yourself said that it was bagseed. Now i'm not saying that bagseed cant be good, what i'm saying is that the seed that you got could have weak genetics and be super particular about growing conditions such as heat, nutes water ph, etc.. like the bubba that i have it is probably super finicky. Good luck with your grow hope that this makes sense. most important search the best genetics that are available to you. Peace