If the tops start to yellow and look N deficient, too high ppfd. Raise an inch. I push my plants hard, so I know what to look for. I've had bleaching, but In my experience has been only buds too close directly below red diodes. It does happen with the cobs, but it's easy enough to pull the top to the side. You'll see the yellowing first. Even tops that are light stressed, will still be good, just not as tight. They turn out a bit like if the temps were too hot, probably cause it was right up close to the diodes. I try to definitely avoid over lighting, or having them too close, but never had much of a problem at a foot. Even less. I still wish my lowers would bulk more. It definitely is strain dependent though. That monkey genius I harvested a few weeks ago is a rock maker. Even the lowers are dense. She grew very nice though, kinda spread herself out, and had very few leaves. That's a nice plant. Slow veg though.
