I was shocked to see my rear disc in the condition above when I was washing my bike this weekend. The slotted rotors came stock with my bike (specific to the anniversary model), and what confuses me is that the wear on the disc only bleeds into this one slot. The other slots on the rotor are relatively deep still, and I can only wonder what would cause the disc to wear so heavily in just one area... warpage, perhaps? Manufacturing defect? The disc only has about .2mm left before minimum thickness, so the disc will need to be replaced nonetheless... but if anyone can offer some ideas as to what might have caused this, then I can certainly avoid having to buy a new disc so soon. The bike only has 14k on it.