I gave all 3 a taste of nutes this week, went half of the books recommended dose and i think one of them didnt like it too much.. She already had one leaf dying but then another one died. Also doesn't help that i broke one of the leaves off on accident. i hope shes ok the rest of the plant looks ok.
Maybe try a bigger pot next time if possible. I use ten gal you could easily put a couple small plants in them and the roots would have plenty of room to grow