Generally looking great! Nice photography as well. As the plant is beginning to send its energy into producing sex cells, or pistils, it will undergo "apoptosis" which is cell programmed death, meaning, it is thermodynamically efficient for the plant to stop utilizing glucose at the lower portions of the plant. Naturally as it matures, the fan leaves toward the bottom will start dying off. This is most likely the case here since the canopy is still relatively lush (IMHO).
Thanks Lee. You know the previous post with the leaf sample pics? The second example are leaves taken from near the top of the plant