Brown Spots?

very stange color hmm if u take ur water from well and it's to much Fe then it's excess could cause P lockout hard to tell with these pics it's not Ca though the symptoms not right i suggest u to change ur water source

Think this is primarily senescence, maybe exaggerated by any cooler temps during lights out ( 68F). If it started as spots, i'd say Ca deficiency. If you've blasted it with too much p or k, could also just be inhibiting it. Visible symptoms are indiscrete as more than one cause is possible. You look fairly deep into flower and canopy is strong otherwise, be patient as to how you react. If you can rule out possibilities go ahead and tweak something, otherwise make sure you are nearly 100% confident before doing something. Unnecessary reactions just make problems worse more often than not.