It is a “bad thing”. Well, not bad, but ambiguous.
When you create a page, the slug is the title with special characters removed. If you create two pages with the same title, the second one will have
-2 on the end to distinguish it from the original. That syntax is for a separate entry in the database.
Pagination is handled with slashes in the URL so it can be parsed unambiguously.
Okay, thanks for explaining…