A Lime Tech Rep reached out to me today and took care of this very quickly. Immediate responses as I sent them the required info so that they could send me a 2nd replacement key.
My system and array has been stable since I replaced the PSU (an EVGA SR-2 1200W for anyone curious) with a new Corsair HX850i.
FWIW, what a horrible, time consuming experience. HDDs just dissapearing randomly, swapping out SATA cables, swapping out HBAs, swapping out drives, all while doing a parity sync in between each swap, which would fail after about 15-20 minutes, with errors on the parity drive at first (which made me initially think that the brand new WD Gold drive was defective.) Then, had read errors on one of the other drives (the only drive in the array with data on it at the time.) Moved each component to a spare system to rule it out as a problem, and after they all worked fine in the other system, I had the PSU left as the next common thing that had not been tested yet. Put new PSU in, and everything worked like it should, and has been since then (about 1 week so far, and counting.)
RIP EVGA SR-2 PSU and 2 USB flash drives. Probably lucky that’s all I lost, now that I think about it.