Your right, that is not normal. Is the other side the same?
You said you stumbled a bit when you installed the kit. If the caliper or rotor is not in their correct positions, it could cause you not getting the pads on properly. I would relook at any literature, rewatch the youtube video and maybe it will strike you as to what is wrong.
If you can’t get any further, I would continue your contact with Brothers. Its their product and they want you to be a satisfied customer.