User lookup autocomplete only shows one result when searching a partial name (e.g. searching 'John' only returns 'John A' even though John B and John C exist).

When importing users by replacing the ost_user table directly in the database instead of using the built-in CSV import (Agent Panel > Users > User Directory > Import), the ost_cdata search/index table does not get rebuilt. Drop the ost_cdata table completely and run cron multiple times until it is rebuilt and fully repopulated. Going forward, use the built-in import feature rather than direct table replacement.