I am giving this plant one last ditch effort before culling. I suspect a possible boron deficiency . The plants were watered with nothing but reverse osmosis which makes it more susceptible to a boron deficiency. The symptoms sound similar and so the plant was flushed with 5 gallons of drinking water on 6/19/19 pH'd to 6.3 due to the previous runoff readings were around 7. Runoff was around 6.5. I then followed up with about 1/4 gallon of drinking water with 2.8 ppm of borax (1/8 tsp per 5 gallons). Guides say if it is a boron deficiency this should provide overnight improvement. I will report back next week on the results. Either I treated it or killed it lol.
Update 6/20/19 - The weight of the pot post flushing caused it to topple over during the night. This uprooted the plant and while trying to get it settled back into the pot, the plant completely snapped. The stems did indeed have a hollowness to them so I believe the diagnosis was possibly correct however, we will never know as this plant is officially dead. RIP!