Rustyness, that's potassium, the fan leaf that's forming a claw is a nitrogen overdose. This can be caused by a cupl things, it being rootbound,looking at how the leaves fold that might be it but I'm guessing it's not, if so its just not sucking up nutrients because theyres no new soil for the roots to latch onto, just repot w new soil, bad ph could be another reason (high ph locks out micronutrients low ph locks out npk) this would be a low ph if anything but again idt that's the problem, Or too much nitrogen is causing a lockout, too much n salt in the plants veins to suck up the p and k. If I had to bet on it I'm 80 percent sure this is just a nitrogen overdose causing a patassium lockout, flush with 3 times the amount of water the pot holds and add a little p and k, also calmag never hurts as soon as it starts flowering, get rid of nitrogen all together you'll want the plant to use the nitrogen stored in its leaves to break down chlorophyll increases terpenes and potency, also need during flower can cause the plant to reveg, so chill with the nitrogen prettymuch, remember less is always better than too much start at a fourth the recommended dose, soon you won't need a chart you can just tell what it needs and feed accordingly