that is phosphorus deficiency. It is normal that the plant pulls phosphorus out of the fan leaves and translocates it to the buds. If any of those single leaves poking out of the buds start to show signs of P deficiency, I would apply a high P synthetic fertilizer. There is plenty of P in the Bloom but for some reason your plants are not able to use it. If you PM me with your mailing address, I will send you some Monopotassium Phosphate that you can mix with RO water and apply to your plants. If it were me, that is what I would do, apply some synthetic P to see what that does.