you might have nitrogen toxicity going on. I think I fed a little too hot the time before last and I got rust spots then yellow and some dying leaves. they have been out in the rain lately and also watered once in the last heat wave and they are starting to get right again.
looking good! I'm excited to see them flower. I still have a ways to go before flower, mine are getting pretty big tho. what is your light on/off times now?