When I try to click on the link for Sion Sono on any of his movies, it lists him as having directed only a single film.
https://www.icheckmovies.com/movies/?tags=director%3Asion%2Bsono
It works in the beta: https://beta.icheckmovies.com/movies/?filter=director%3Asion%2Bsono
Here’s the rest: https://www.icheckmovies.com/movies/?tags=director%3Ashion%2Bsono
I guess imdb had a different romanization of his name before, and tags don’t update even though the names do.