Strange Brown leave

Can you update your diary with the nutrients and doses that you're using? Diagnosis will be much easier if we know what is being fed. Darker green leaves with a shiny kind of plastic looks to them and slight curl, makes me think there's at least a nitrogen toxicity. Dark foliage can be a sign of magnesium toxicity as well.

Burning from over feeding...........nothing more, nothing less.

looking a bit overfed. Any time I see markings on leaves like that its normally from PH/root issues. however I also normally see them on the lower growth first not the upper. I would lessen the feed and see how it reacts.

Uhh yeah better get rid off it or check this bud from the inside, could be a bud rot as it develops from the inside, not cool but you can only carefully crack this bud up and check

Hello mate, it's very diffucult recognize it only with this photo and in your diary also there aren't others. It could be a lot of things, you might cut the leaf to avoid any contamination if this is a fungus or mold. Good luck and happy harvest!