That most likely means that the zooxanthellia is multiplying due to more sufficient light. The LFS probably didn't provide it the lighting it needed for the algae to grow, therefore a bleached (white) anemone. Fortunately for you it needs that symbiotic relationship with the zooxanthellia to be healthy. The fact that it is browning means that it is healthier (and happier) than it was at the LFS. You may find that you need to feed less now since it gets most of it's nutrition through symbiosis.