There should be no over hang of the pad area on top of the rotor, ever. Ive used countless different pads on rear Brembo's and never had it. Thats a design flaw in the KNS adapters.
Are you running pad shims? I personally found that pads without them wear differently to ones with shims as you'll notice the shim is only a half shim across the piston face allowing the pad to press on a slight angle to the rotor which gives more even wear.
Ive also seen this a lot on calipers Ive received to refurb.
