Mine has been bleached for 6 months now. No change, split once, slightly smaller. I tried feeding it soft corals in hopes that it would maintain its food's zooanthallae, but it spit the surragate toadstool leather i fed it out the next day, undigested.
From reading up as much as I could on the subject, this is the conclusion/theory/opinion, whatever you wanna call it

that I have came up with.
Bleaching supposedly occurs because the zooanthellae in the anemone is no longer adequate for the current conditions (e.g. salinity too high, less lighting, more lighting, temp change, ect...basically any stress causing factors. In nature the anemone/coral expels its zooanthallae in order to "exchange" it for a more suitable type for the new conditions, this happens easily in the ocean due to the varyity of zooanthallae clades in the water coumn, however in our closed systems, an anemone might regain color in a week to a year, maybe never, jsut depends on whether or not it can find an exeptable zooanthallae clade.