Plants dropping

For the last week I have noticed my plants droop as if they are sleeping about 3 hours or so before lights out I’m at 18 inches above the canopy with a 240w farmlite on 47% intensity with the photon app using a paper diffuser these plants are sitting between 390 - 450 PPFD around the tent this shouldn’t be nearly enough to be to much light but I also have two plants that are tacoing and the leaf temp with a thermal gun is 69F can anyone please make sense of this ?? All plants droop hours before light out and two plants have tacoing issues as if it’s to much light intensity plants are 1 month into veg so PPFD should be able to go to 600 and I’m not even at that I’m doing a 18/6 hour schedule with photoperiods