The fan leaves died, just as they usually do late into flowering. I have a NL plant that started flowering at the same time and many of its fan leaves are still alive and green, plus all of its hairs are still white, unlike the AK.looks like they have some fattening up to do yet. 6 weeks ain't long really. Get yourself a pocket microscope and check the trichs.
What happened to the fan leaves? Ph problem?
Drink!
good point. I don't think it was ph problem because I would test it regularly. Do you think it could be caused by a too strong nutrient solution? My solution is usually up around 2000 ppm, sometimes higher.That is not typical yellowing from lack of nutes. I would think you may of had(have) a mite problem...and possibly a ph issue. Something looks locked out.
I know lots of folks like to have everything yellow up at the end....but I don't see things that way. A healthy green plant right to the end has to be more beneficial than a dying plant starved for food.
Outdoor plants don't die off like that before harvest...at least mine never have.
Drink!