I really hope its not, i have been cutting down N very rapidly and had an extreme fungus gnats infestation at some point so i think its what caused thise leaves to brown up+ I ran out of space in the tent and the light is too close so that could be a reason as wellI agree with others that the plant hasn't really reached its full potential, but all the brown/dying sugar leaves in that big cola probably means mold/rot inside.
It might not be, but I'd at least pry open some buds to check. Anytime I've had dead plant matter inside a huge bud like that, it's always ended up being moldy...