In reply to Inhambane:
I don't think it's defective. I've also noticed that the Petzl reverso alloy is really soft. I've retired two after they started chafing at the rope on absail where opposite edge to the teeth had worn sharp. I've not had this problem on black diamond or dmm belay plates so I assume it's something to do with the metal used.
I had just put it down to use, and wasn't too bothered, as I consider all my gear expendable and I don't mind replacing it. Seeing your wear which is exactly the same, I will email Petzl as well and see what they say.
In reply to whoever said that the William is a 'master point' crab, I think this is misleading. All carabiners with a round back bar (i.e. Not small D shaped one) should be fine to belay off, and designers should expect moving ropes to be put across them. I think the review is more suggesting that it's good for a master point due to the size and ability to take multiple clove hitches, and that the bulk and weight don't make it ideal for belaying off. I actually disagree as I think the size is perfect to make tying off a belay plate easy, when using half ropes.