I'm halfway through flowering my 2nd grow room, so i'm still kinda learning as i go, but i have had that happen to a few plants in both, at first i was a bit worried and thought it was some kind of lack of even light hence the twisting, so as well as the reflecting sheeting i have over the walls i also lined the floor and even used smaller squares over the tops of each pot, but after not bein able to get a definate cause and solution after hrs of searchin I just tend to leave them be and it either sorts itself out or seems to cause no ill effect if it doesnt.