The tags seemed a little mixed up at the garden center... There were two flats by each other. One was lime green with Silver leaves and the other was this reddish brown hue. Both flats had a few tags in them saying "Silver Beacon" and a few saying "Purple." Yet it looked like one flat was clearly one kind and the other clearly another kind.
"Silver Beacon" says it has green edged leaves that turns "bronze" in the cold weather.
Maybe this is Bronzing.