alt Hacker NewsGoogle is not flying over the area itself right? perhaps they where using source maps with some sort of license agreement and the license expired, or there was a dispute.
It seems to me that it is in the favor of Google to gather the most up-to date maps, even if they can offer them in a limited window.
I wonder if the same is true for Google Earth, since I believe that uses higher quality / different maps in a lot of area's. (don't have it so I can't check)
This was my first thought. The simplest explanation is that they lost access to the recent imagery. If you were going to build a system like this, you'd show the most recent imagery for an area that you have access to. If one of your license agreements ends, it might mean you end up showing less desirable data, but at least you're showing data.