The proximal ring of the graft sits in a plane perpendicular to the neck. Unless the X-ray beam lies in that same plane, the ring projects as an ellipse and its upper edge climbs toward the renal ostium even though the fabric has not moved. A second trap: the proximal covered stent and its bare suprarenal struts are one rigid unit. They do not bend with the neck, so in an angulated neck the stent leans on the outer wall and the fabric edge stands off the inner wall as a lip. Drag the 3D view to rotate it.
Move the sliders, or press Play to walk through the usual trap: an angulated neck, an AP beam, a ring that looks like it covers the renal, a graft pulled down to compensate, then the C-arm squared up to show what was really happening.