As you probably suspect, this wear is not normal. They should be wearing evenly. Are these the pads that came with the kart and have you done anything to the brake system?
Because there is one piston per side, the pads should be pushed straight in. Replace the pads and the special bolt that goes through them. Look for any issues with the caliper during the replacement that would prevent the pads from moving in straight and that both pistons are functioning. Center the rotor between the pads when your done. Acquire a brake bleeder and brake fluid. Believe you have an EVK and that should have DOT 5 brake fluid in it. Unscrew the brake reservoir caps and if the fluid looks purple, it’s DOT5. Between three day race weekends, I bleed our brakes.
Now, watch the wear pattern.
FYI – Rebuilding the master cylinder and the caliper is fairly simple. Bleeding them can be a pain.
LAD Specialties customer / tony kart / rotax / kt100