Couple of things i notice from the last round of pics is purple/redish on fan leave stem i've found that that is number 1 sign of Nut. lock exept for in a few strains where this is a continued trait. Saw that you were flushing in earlier posts i would flush heavily. What is your soils PH?Temps in grow area? distance of light? From pics it looks like you have a (Mg) Magnesium deficiency in the late stages. Have heard that watering with 2 tsp of Epsom salts(magnesium sulfate) per gallon of water or make up a foliar spray if this starts to green things back up you know that is your problem. This can occur pretty commonly in acidic soils (PH below 7). Next round balance ph of soil or check that it is stable before planting.