Damn that's a weird one.. Try deleting all history - then export as obj and reimport to a new scene. Also try create a standard cylinder and see if it happens to that as well.
When things like this happen to me I'll export the mesh as an obj with nothing checked, then reimport it. Usually solves every weird issue like this - Good luck!
luther01.obj (click to view in 3D) Almost done with it.. gonna add a base and render it with marmoset, hopefully tomorrow. Was supposed to be for the artbypapercut competition, but missed that deadline by a mile.
Try exporting the model as an OBJ then importing it again. Sometimes this fixes meshes by exporting it to a simpler format then using that. May need some clarification though. Worth a shot?
Thanks Brandon for the uploading the obj and the photos. Defiantly going to use these as topology references. If you don't mind me asking; is there a significance why you twist the arm?
You can do this: http://www.unifycommunity.com/wiki/index.php?title=TerrainObjExporter Export the terrain to an obj, optimize and bring that geo back in for your sweeping ground plane.