If you play a map that does not contain any edge file, sometimes soldat will randomly select one from the edges folder and use it on the map (even tho it shouldn't have any).
Example:
Map with no edge: http://tinypic.com/fnwupw.jpg
Map with random selected edge: http://m00.laughingllamas.com/data/sgtbeaver/muckedge.JPG
Example:
Map with no edge: http://tinypic.com/fnwupw.jpg
Map with random selected edge: http://m00.laughingllamas.com/data/sgtbeaver/muckedge.JPG