Hey there, I know your question is a little older now, but have you considered that it ciuld be light bleaching from the led? I only think this because its only the top most leaves affected....except in this week im seeing some minor drooping accompanying the bleached tips, which is actually another symptom of light stress. Since your lights are on 24 hours and leds can be a little unpredictable at times that's what I'd go with.
Your nutrient schedule does look strong and heavy, but if you've been doing it for a while and things arent getting worse, like more discolored leaves, top and bottom, leaves falling off etc, i think you could rule that out....but watch for any worsening symptoms and then i may he wrong.
Perhaps try lowering your hours just minimal to like 22/2 or 20/4 and see if that might help? I don't think it will take away from any yields. And might provide a short rest for the plant.
Happy flowering ✌️