Fast sweet

Hello My opinion would be calcium deficiency, those copper rusty spots are an immediate cal thought for me. But i see you have calmag in the diet. Some plants are very calmag hungry so it could need an increase, otherwise its maybe not being taken into the plant because of a ph level or sometimes high potassium will block it out. I think the cool temperatures will change your bud color, and sometimes the leaves but its more of a whole leaf change versus spotty changes.