In the old Hosted version and the WordPress plugin, the "Author" can publish the event without permission, which is not the case with the "Contributor" role, this is the definition of both roles:
An Author can create, edit, publish, and delete only their own events, as well as upload files and images. Authors do not have access to modify events by other users.
A Contributor can create and edit only their own events, but cannot publish them. When one of their events is ready to be published or has been revised, the Administrator needs to be notified personally by the Contributor to review it. Furthermore, once a Contributor’s event is approved and published by an Administrator, it can no longer be edited by the Contributor.
But the problem is that there is no "Contributor" role in the new version.