It happens. I had a Kasumi brand 3/8k stone That was marked differently to what it said on the box.
In the past guys have had to lap off up to 1/8" on the norton 4k (white side) to achieve a clear surface. Possibly your 8k is faulty like that ?
Of course appearances can be deceptive & I can't actually see the scratch pattern on your 4k pic but if your edge is chipping there's something wrong