Search Supervision On - No Search History for any Child

When I recently checked the search history on all of my children's Norton Family accounts there were no results.  The web history shows up (if they click on something), and shows allowed and blocked sites.  But the search history is completely empty on all accounts.  Search Supervision is turned on for all family members, as is content filtering.

Why am I not seeing searched phrases?

Does this require a browser plugin or something?