This happens on the top level assembly drawing only, the sub-assembly drawing is OK. The part is simply a extruded half-round gasket where the long axis vertical and is assemblied as part of a circuit card. When in hidden line view display and oriented to a trimetric view the half round edges display fine, but in an iso view or close to it they will not. In wireframe the edges show in any orientation. I've tried modifying the edge display and member display, but it was of no help.