Location search, including leaderboard location search, breaks whenever you enter an additional character while the server is processing a location search completion request. The search just stops working with an HTTP 500 error code, and you cannot recover from this state except for reloading the page. Note that you cannot assume the same quick response times in your office for all other clients on the web.
I am trusting that you already know how to fix it. 
Btw, whitespaces should not trigger a request.
