If you take a look at this : https://codesandbox.io/s/2wy7v2orwr?file=/src/Map.js
you will see you can search things on the map, but if you zoom-in somewhere randomly(deep zoom in, for example somewhere in the ocean), the search is unresponsive , i.e. it doesnt give any results in the result dropdown. Why is that?
You need to set the useMapBounds option to false when you create the geocoder.
May I also suggest you try react-esri-leaflet, which has a ready made esri-leaflet geocoder component for react-leaflet.