I personally dont see anything that would make me think of budrot, I would definitely wait it out, those buds still got some weeks to go. I really wouldnt suspect bud rot given the stage of flowering. Seems like possibly quite a nute burn? You write in your grow journal you have 70% air humidity, that does strike me as high for flowering tho, and could potentially lead to budrot from my experience so I would personally lower that. Best of luck with your grow! :)