I'm in coco/perlite under a MH at 400w approximately 17inches or so from the top of the canopy.Are the leaves like that near a heat source or all over? What medium do you grow in?
I notice the light turn on a hour early a couple weeks ago and this was using a mechanical timer. I've been watching it closely since... humidity hovers between 40-55% and temp at 18-28 degrees celcuisLooks like something else is going on ....
3 finger leaves. Have you been running irregular light cycles ? Or other stressors.