I have contacts that are employees of the company. But I noticed that when I filter partners (contacts) as Employees only, most contacts of the company are not appearing. When I added the column in the Contacts list for Employees field, that's where I noticed they're not tagged as such.

But the weird thing is that viewing these contacts show that there's a smart button to their Employee profiles (in the Employees app). I'm not sure if this is because I manually created these contacts before I installed the Employees app.

How can I ensure proper tagging of these contacts as Employees in the Contacts app as well?

EDIT (hopefully to clarify further):

1. Contacts were initially created before. These also were created as the Company contacts.
2. Employees app was then installed.
3. Corresponding employee records were created in the Employees app.
4. Employee records automatically have the Contacts smart button.
5. The corresponding Contact records now also have the Employees smart button.
6. But if Contacts list is filtered by Employees, most do not appear, even if they have linked Employee records.
7. If I add the "Employee" field in the Contacts list view via Odoo Studio, I would see these contact records having untagged Employee attribute despite being linked with records in the Employees app.