Contacts are not visible in List view but able to see in Hierarchy View

Summary:

In Accounts we have Contacts and Relationships, but for 2 of the contacts we could see the Relationship but that contacts are not visible in contacts tab under accounts

and when we click on hierarchy view we are able to see the contacts.

why not in list view.

We tried to get the all contacts of that account using Rest API , but there are also we dont see in response.

any idea about the reason why it is not appearing in contacts (and this contact is primary contact to the account and we can see in Relationships as well)

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