Your search bar dropdown suggests destinations where you have no properties listed.
Why this happens. The suggestions come from the destination lists on your site: the Cities and Locations attached to your properties, found under Properties > Cities and Properties > Locations in the WordPress admin. Entries with a count of 0 are leftovers with no listings behind them.
What you can do. Delete every Cities or Locations entry that shows 0 properties. The dropdown then lists only the destinations that have listings. Nothing changes for your properties; they keep their own city and location.