Problem when trying to create a non listed credit with a name that already exists a few times with roman numerals

As you can see in the picture below, I am having trouble creating a new imdb person that is not listed yet in the platform. There are already 8 people with that same name, and this tells me to create it with the VIII when there is already somebody with that name. Why doesn't it create a new one with the IX number? Is VIII the limit or why doesn't it recognize it? I've seen people with an IX next to their names. Thanks!