Thanks for your input!
I get it for sure. None of the other 3 are doing this but from what I have learned, I don't think it wise to give any N at this point. I have just given them the last feeding of the grow and now just giving water and molasses to finish. Early when I first noticed this, I assumed it's a deficiency in N. But I did give extra N, I think after week 5, I'd have to look at my notes. And every feeding through this last 3 or 4 weeks have had a total of 5.5 in N.
I don't think it's looking dead at all. But the yellowing is slowly progressing upward. There is no new growth except at the flower sites. In the pictures I included today, you can see the plant in the back left. It still looks quite good despite the yellowing leaves below the canopy. In fact, if it keeps going the way it is, I think it will be the highest yield of the 4.
I guess it could be some form of lock out but since none of the others are doing the same thing, not sure that would be it.
My guess is it may be genetic related. These plants are all supposed to be GG#4 and yet they all look very different so it could be that. Who knows if they are really GG#4?