Contact App, copy in the Address Book

Maybe is a stupid question but, when i try to create a new contact in Contact App, if i change the Address Book (we have two address book, one for each User called Contact and one address book called Shared that is created by one user and another one user can modify) the Contact is duplicate in two Address Book…is like a “snapshot” of contact until it was change the AddressBook… there is a method for deny the copy between Address Book, when do I change from one Address Book to another?

My Installation is Nextcloud 16.0.5 and Contacts Apps is 3.1.4 version,