Even after enabling "partial match search" in the Lookup settings, some registered records may not be displayed as matching candidates when you try to retrieve data.

The index of the app used as a datasource is probably being updated.
Please wait until the index update is complete.

Note that the time required to update the index depends on the amount of data in the app used as a datasource and the system load.

During index updates, filtering in Lookup works as follows:

• Even when the Enable partial match search (Recommended) is selected, filtering operates as if the setting is disabled.
• Even if you add or edit records in the datasource app, the new or updated records will not appear in the filter results.

Once the index update is complete, "partial match search" will be enabled, and filtering will be performed based on the latest record data.

When you check Enable partial match search (Recommended) in the Lookup settings and then activate or update the app, the index for the datasource app is updated.

This update runs only once for each datasource app.
After the index update completes, it will not be performed again. This is true even if you disable and then re-enable "partial match search," or configure new Lookup settings to retrieve data from the datasource app.