Rusty/copper dots on leaves

It could either be the PH value or the plant is already pulling the remaining nutrients out of the soil to get ready for the harvest, so everything is actually good, the buds look really nice, keep it up :=)

You need to start flushing for around 1 week and cut it when the time is right

Looking at your diary, your ph should be more acidic then 7. A 6.5 if in soil. The markings based on stage of growth is a potassium deficiency. In bulking they like a lot to develop the colas. You look to be almost done, and likely going to a fade. So there is not much you can do but stop it if your still giving nutrition. During fade this would not matter. It's just a final stressor as it ripens.