Mystery grow - 2x photo, 2x auto

in your very first photo is looks as if the light reflecting off the bent tip of the leave is white and powdery but I think that's the light. I do agree with the other your looking like a excess of N is causing all the leaves to be real dark. Will want to get that in check before it causes some other issues. Good Luck!

I don't see any, but you do need less nitrogen and more potassium in your feed. Flowering NPK ratio is 1-2-3. Brown straight tips on leaves is potassium deficiency sign. The shade if green says how much nitrogen is in the plant. Try to keep you rh between 40 to 50. Above 70 rh and you will have issues for sure.

I'm not seeing any powdery mildew, thankfully... I'm seeing what might be some insect damage (maybe spider mites, maybe thrips) .. I would get some Dr. Zymes Eliminator or some Spinosad and if you see an increase in the small white markings, get to spraying with either one of these - they're both organic (although Canada does not consider Spinosad to be organic for some reason) and can be sprayed all the way through to harvest if need be... If you need to use either one, always spray just before lights out.. Good luck!