What went on here??

Flushing a plant in stress can cause more problems than if nothing had been done. Flushing is a last resort for when the substrate has become nitrified or otherwise toxic and not a cure all. It will also severely affect the soil microbes negatively, which are vital for soil and plant health. Your plant going this yellow is due to reducing the nitrogen too early in its flowering cycle, causing the plant to "cannibalize" itself. Flushing excessively just removes even more nutrients from the substrate, further compounding the original problem. Yes, you should have waited a bit longer and yes, your plant does look washed out. I hope you are not too upset by my "brutal honesty" and my "tell it like it is" style, some people can't handle it, but there is no way to wrap some things up to make everything seem like sweetness and light and wonderful. Besides, life isn't always fair and there are no participation medals in real life. At this stage I would resume feeding bloom nutrients for another week or so, then cut back to plain water for another week or so and harvest then, roughly. I would also unplug that humidifier asap, your plant does not need it and those brownish blotches on the leaves look like the beginning of a fungal/rust attack. Hope this helps, Organoman.