Vanilla kush problems at 6 weeks flowering

Hi, my vanilla kush hasn't had a problem my whole grow. Now she's 6-7 weeks into flower and all the fan leaves are yellowing, spotting up, and dying. I've tried flushing and stuff, nothing seems to be slowing it down. Can anyone identify the problem, and have some advice on how to fix it? I don't want the whole plant to die off before the buds are finished.

That far into flower you would see them yellowing.

When in doubt, flush it out.

I've grow out VK 2x and both times the fan leaves dried up and fell off don't sweat it the smoke turned out great.

Ive grown the Vanilla Kush a few times.
Its Magnesium.
Add some Cal/Mag, a little superthrive in some reverse osmosis water and give your soil a good soak, youll be A-ok in a few days.
The leaves that are fuct up will remain fuct up, but the spots and the yellowing and dying of leaves will stop.

Start brewing some compost tea with a little kelp meal, some lemon juice, molases, a little bit of Cal/Mag, and a pinch of sucanat or brown sugar.
PH it to 6.7 and pour a cup or two of it on each plant 2x a week.
10 days before harvest, give your plants a good flush with plain water.
Then stop watering it and harvest right when your plant starts to droop, and youll have the best smoke in town my friend

I have a couple VK's in veg @ the moment.
Your pretty far into flowering . It is going to be a rough finish.
Root bound. to late to transplant.
I would like to suggest next time you grow. Mix in some perlite into your soil.
Buy yourself a couple smart pots.