Problem with headless body

[Helios]

Exception drawing Human_Corpse15633556: System.NullReferenceException: Object reference not set to an instance of an object
at Verse.PawnGraphicSet.HeadMatAt (Rot4 facing, RotDrawMode bodyCondition, Boolean stump) [0x00000] in <filename unknown>:0
at Verse.PawnRenderer.RenderPawnInternal (Vector3 rootLoc, Quaternion quat, Boolean renderBody, Rot4 bodyFacing, Rot4 headFacing, RotDrawMode bodyDrawType, Boolean portrait, Boolean headStump) [0x00000] in <filename unknown>:0
at Verse.PawnRenderer.RenderPawnAt (Vector3 drawLoc, RotDrawMode bodyDrawType, Boolean headStump) [0x00000] in <filename unknown>:0
at Verse.PawnRenderer.RenderPawnAt (Vector3 drawLoc) [0x00000] in <filename unknown>:0
at Verse.Corpse.DrawAt (Vector3 drawLoc, Boolean flip) [0x00000] in <filename unknown>:0
at Verse.Thing.Draw () [0x00000] in <filename unknown>:0
at Verse.ThingWithComps.Draw () [0x00000] in <filename unknown>:0
at Verse.DynamicDrawManager.DrawDynamicThings (Verse.DrawTargetDef drawTarget) [0x00000] in <filename unknown>:0