Thread:Digi/@comment-39007672-20200212154400/@comment-691135-20200212221413

Interesting. This could be another case like the Dekaranger blurays where Doggie's name was spelled Kluger despite being shown as Kruger in the show itself. And also, like you said, grammatically it doesn't make sense. It could also be a misprint - the person might have heard "Izu" but thought they meant "Is" and wrote that. This would be consistent with the Premium Bandai link Destiny Shin shared above.

For now, I would say not to change it. Maybe list it as an alternate spelling, like it is now, for the time being - but use Izu officially.