Brown spots on top leaves - nutrients, light or something else?

I’m seeing two things right now with the plant. The yellowing of the older leaf is a result of Nitrogen deficiency. This should not happen till late into flower. Might want to give a dose of Nitrogen to your plant now while you are still in early flower stage. The brown spots look like the start of a Calcium Deficiency and can easily be corrected by using a CalMag product. Follow the manufacture recommendations for using and you should stop seeing them. I hope this helps.