My guess is that you are importing on the same site multiple times. EDI remembers pages already imported and skips them, unless you reset it. This allows for someone to retry a failed export without duplicating all the content.
To reset EDI on the import site, click the Support page under the Import menu, scroll all the way to the bottom and you’ll see the button Reset Import Settings.
If you are importing to the same site for testing purposes, I’d recommend using WP Reset or similar plugin to make that installation a fresh WP install.