Why does my geolocation return "Shuzenji" sometimes, instead of where I actually am?

I’m finishing up the front end development project, and my weather app most of the time gets the location right, but maybe 1 in 5 times it returns “Shuzenji” instead of wherever I actually am.

Here’s the pen:

Any idea why this is happening?

I think that is a known bug of the server.