this is so drastically different from anything else in the series that I think it should be the work of one of the two outliers on the episode, Okamura or young Gosei Oda and between the two it definitely seems more like something the former would do. These CG long shots appear in so many of his OPs and EDs, just here it looks drawn over at times, in addition to that the art also looks fairly uncorrected.

But at the same time, he had just finished with Wolf's Rain so I'm not sure where he found the time and he also rarely does KA during this period so it's difficult to say