I also think it looks a lot like heat issues. There may be bugs as well, hard to tell, but theres some wild leaf canoe going on which to me is a big sign of heat stress.
Op, please give some more details of the grow. A side picture of where the light is in relation to the plant would help and the whole plant itself in a picture would also help. Details of feeding, what your feeding, how often, ppms, ph, light type and distance from the canopy, water temps, room temps, root color, rez change schedule, all that and more, then maybe we can come to an agreement.
If you have a magnifying glass it would be a good idea to check the leaves as somone has stated it looks like bug damage.