MacOS: Contacts doesnt sync properly

Your MacBook Pro must have a corrupted Contacts database.

Signing out and back in to iCloud isn’t fixing anything because your MacBook Pro is reusing its local database, and thinking that everything is up to date. Updating a contact is what “rebuilds” its entry, allowing it to be displayed.

Try wiping your local cache to force your MacBook Pro to re-download all of your contacts from iCloud.

1. Sign out of iCloud.
2. Delete ~/Library/Application Support/AddressBook.
3. Delete ~/Library/Caches/com.apple.AddressBookSourceSync.
4. Delete ~/Library/Saved Application State/com.apple.AddressBook.savedState.
5. Delete ~/Library/Preferences/com.apple.AddressBook.plist.
6. Restart your MacBook Pro.
7. Sign back into iCloud.

Your contacts should all download fresh from iCloud.

(Note: Steps 2 & 3 are really the crucial ones, but the Contacts.app doesn’t have much in the way of preferences, so might as well be thorough.)