As she approaches harvest time, the lower fans and some lower (interior) growth will die-off on their own. As long as the yellowing and blotching is limited to the fans, and as long as the buds continue to fill-in...all should be ok. (but a picture would really help)

I'd keep her going till you see nothing but cloudy trichomes. (clear trichs=underdeveloped, cloudy trichs=harvest at any time, rusty trichs=starting to over-ripen...harvest soon or risk nanners) Until you witness the whole process, it will remain a nagging mystery filled with panic and overcorrections.

If the buds start weirding-out or mold or some other condition starts affecting them, then harvest at your discression. But if the primary and secondary branches are chugging along just fine, harvesting now will likely cut your yield in half, and you'll lose some flavor and effects. You're near the finish line...don't quit now. :jointsmile:

I treat my NL as if a sativa. Limited nutes when mature.

At this point, with your previous problems, I wouldn't go up with the nutrients.
A picture would explain a lot, if you could manage it. :thumbsup: