Resource Directory - Search Not result not retrieving details for some employees

Summary

Resource Directory - Search Not result not retrieving details for some employees

Content

Dear All,

When searching for a person in Resource Directory > Identify Resource with Usage Type as "HR Employee" , the person record not returned in the search results.

This is applicable only for some random few employees . 

We have tried all the below processes.
a) Send Pending LDAP Requests
b) Retrieve Latest LDAP Changes
c) Synchronize User GUID
d) Refresh Person Search Key Word

Tried the Audit and Flattening of Resource Org Tree. 
But still no Luck

Hence, any clue on this would be much helpful.

Regards,