Search by National Identifier Inconsistent Result Across Redwood pages

Summary:

We have enabled National Identifier search for Redwood pages and completed all configuration steps, as per:

Inconsistencies are encountered across different pages under My Client Groups. Searching for the exact same National Identifier returns different counts of results across pages and some active employees with this NID is not included in the result.

Is this the expected behavior and should searching by National Identifier return all employees with the same primary identifier?

Please help, thank you

Content (please ensure you mask any confidential information):

No result for Personal details page, but with 5 employees in Employment Info page.

Also, the other employees did not show up in the results.