Thanks again for the reply!
What’s throwing me, is that all the deficiencies like that seem to illustrate yellowing, and occur on the edges. This symptom has literally zero yellow involved; just darkens, then turns brown. I think the yellow hue you saw in my photo was from the flash shining off the leaves. Here is a close up of the right leaf you circled in my photo, you can see today it began turning brown, no yellow and it starts in the middle of the leaf, not the edges:
I understand the thinking of being root bound, however as mentioned this problem has existed the entire grow once it was transplanted and moved under the LED, even when it was a tiny plan in a big 3 gallon pot. So, I don’t think it’s because the plant is root bound. The last and only time this plant looked proper green and happy, was when it was root bound in a coffee mug on my window sill getting crap natural light. I can’t believe it was doing better under those circumstances than in a proper setup with care and attention.