Rattling focus ring on Canon 17-55

Few days ago I received the second copy of the 17-55 2.8, and the focus ring has some vertical play resulting in a rattling sound, as if it was a tad narrower than the space that is limiting it. Overall performance of the lens is superb and so is manual focusing, the ring performs as it should, but I am just wondering, whether it's normal or maybe I've got a faulty copy again.