When a user marks a file or folder for offline use on Box for iOS and the item is updated from another device or by another user, the initial user will see a prompt to "Update" next to the item.
Selecting Update will begin downloading the new version of the item.
Box for iOS, Box for EMM for iOS
This is expected behavior.
To ensure that Box users are not working on outdated content, we require that users update files marked for offline when new versions are created. In this sense, the Update option is a shortcut to save the new file.