I checked Known Issues to see if the Kohya notice was still there a month after "working on a fix" for an "identified [...] cause" and saw it was absent. Not wanting to get anyone's hopes up I threw the model I was working on into trainer yet again and waited before making an article on it. It failed, but at 13/15 epoches (usable. Sample gallery made and launches in a bit over 2 hours). Does it work now and I just got a random failure despite it, or is still broken, now an "out of sight, out of mind" on Civitai's part, and I got lucky?