when a guest searches, the Airbnb system only shows the top 300 listings that would appear on the map.
If your listing is not in the top 300, it will not appear. (Which is apparently the case when you first search for "Copperopolis".)
When you move the map, you are changing what listings might appear. For example, when you zoom much closer to Copperopolis, there are only 9 listings (yours is #4 on that list).
When the map shows a much wider area (as it does when you first type in "Copperopolis") there are more than 300 listings, but your listing might not be in the top 300.
If you improve the search ranking of your listing, then you appear more often in the top 300 (even when the map shows a very wide area).