Strange behaviour of Windows search box on taskbar

Sorry, but I can't find such a setting. If I go to Settings->Privacy & Security there is no option "Search Permissions". If I select "Search" then the options I see are "search history" (on), "show suggested search results" (off for web results and on for Microsoft Store), "search my accounts" (off), "find my files" (doesn't do anything if clicked and doesn't show anything) followed by many "related resources". This is true on all three machines. Maybe I should add that they are all signed in with local rather than Microsoft accounts, and that the situation changing when WiFi connected may perhaps have been coincidental.