I noticed that once you've added a volume number you can change it to another number, but you can't remove it, the last number will still show up on the series page. https://www.comicogs.com/comic/120864-ghost-ship
It's also not possible to add a zero as volume number, it does not show up on the series page.
It's not just a problem with those two releases, i've seen the same problem on other submissions too.
Nevermind my 2nd example, i just realized that collection volume numbers don't show up on series pages.
Sorry, nevermind my last post.
The problem is that the 0 for collection volume doesn't show up on the sub.
The same goes for issue numbers. Once there is a number entered it can't be removed anymore, only changed. So if a number is wrongly entered, when in fact no number is given, there is no way to correct that anymore.