So...quick thought. My LED lights are VERY close to the top of the plant. Could this be light burn? I used my phone and got a reading, at the top of the cola, of 170000 lux. I noticed that the new leaves are okay and the old ones are not. Plus the sugar leaves at the very top seem to be in the worst shape. Lastly, the dead leaves don't drop off, even with a tug. I need to cut them off or they just hang there, dead and brown, but still firmly attached.
Sadly, I'm using a small grow tent and the light is as high up as it goes. I've moved the light to the side for now so it's not directly over the center of the plant.