Apart from PCB manufacturing tolerances (or possibly intentional modifications by the PCB house) visible in the example, it's exactly what you can expect when placing BGA pads on a copper pour (or traces wider than the pad).
I understood the original question so that the OP intends something similar, thus I showed this real world example to illustrate possible side effects.
In the present design, the copper pour is preferred to achieve low connection resistance for a switch mode regulator. I agree that the pad finish look curious, but I feel that it's still the best option in this case.