Do they look like that the whole time under light or just towards the last few hours of light? Mine drooped in the last hours of lighting sometimes and it seems to have been from under watering. I bumped up my next few waterings, making sure to get some run off and for the last few days the leaves have been at attention the whole 18 hours now. It could be nutes, it could be strain, or heat.. what type of light are you running?