Shows exactly what I am talking about. It's also not a visual bug because I have tested settling the area and it provides 52 food as on the tin (with a bunch of food wasted of course). There was a volcano around that area before but I have yet to see this happen with any other volcano so I am convinced it's a bug or some feature I did not know existed. Save for anyone wanting to mess with it.
Edit: I should clarify that this is SVN, not V34.