Pad carrier post clearance. Interestingly, the rotor is riding right in the center of the caliper but the outboard carrier pins were lightly contacting the rotor surface. Removed calipers again & trimmed the outer posts by 2mm making them match clearance of the inner posts. Painted the exposed metal with high-temp yellow ceramic engine paint. Had to do this on both front calipers. The gap from the pin to the rotor is less than the thickness of the pad carrier so no risk of a pad coming out.