I could be wrong as I don't have extensive experience but I am inclined to think those plants are starving. You said initially that you had nute lockout and then you flushed and only watered for a couple weeks. I don't know the FF soil or nutes but I know that with organic feeding, the nutes take time to be chelated by the microbes in the soil, and if your microbe level is low to begin with, then it will take longer.
If you have this occur and you get impatient and add extra nutrients, you can cause an over-fert or chem imballance that creates a lockout situation. When lockout occurs the plant is not able to feed itself. Then when you try to correct it by flushing, you still are not getting any nutrients to the plants.
Once you have flushed and are certain that you have PH ballance and are no longer in lockout, the plant should be able to feed again. However, if the original problem of not having chelated(available) nutrients to a plant that is now in high energy growth(flowering), then they will continue to starve.
I am not sure if the FF nutes are chelated or not. If they have available nutrients in them, then I would continue feeding them lightly, and continue to increase the mixture until you get back to standard strength. It may take a while for them to recover as they are going to be trying to move all nutrients to the now forming buds rather than the damaged leaves.
I wouldn't knock FF products as I have never used them, but that seeming lack of control and the experiential learning curve is why I prefer using nonorganic hydro for growing. I am able to micromanage the whole growth and nutrient level of my plants. It may be just me but nonorganic seems easier to learn the nuances of growing plants.
Green Mojo to ya Brother