Late flower nutes

After looking at pictures, i'd lean toward senescence and maybe sub 68F temps at night for the red/purple. The autumn colors can also be unrelated to environment and caused by genetics. The green leaves look lush enough in pictures, otherwise. I usually assume they are a tad darker than what they present in pictures under grow lights, too. The taller plant in back has a bit more fade going on. but might jsut be angle of light in picture. 3.5 weeks left? have you checked trichomes with a scope? Don't take any breeder's advertised flower time as a precise value. it's just a ballpark and some will deviate more greatly than others. trichomes, bud density, coloration/retraction of pistils are all important factors to consider. Not all plants will cotinue to bulk up. if it's not adding layers of new pistils, it's probably not going to bulk up. Waiting for it to happen can come with its own risks, like an increase chance of hermie... last ditch ever to get knocked up before imminent death. the previous growth keeps aging too.. i'd wager it is somewhate neglected by the plant since it serves no more purpose, like how a lower leaf completely blocked from light will be shed.

Yes feed water molasses epsom salt mix 🚀