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This cable and connector were discovered on a job where someone tried to isolate the equipment grounding conductor. If you look close, you'll see the insulation covering on the light green cable is continuous right on through the connector bolt head. The "bug" is even attached backward.
As per 110.14(A), "Connection of conductors to terminal parts shall ensure a thoroughly good connection without damaging the conductors and shall be made by means of pressure connectors (including set-screw type), solder lugs, or splices to flexible leads. Connection by means of wire-binding screws or studs and nuts that have upturned lugs or the equivalent shall be permitted for 10 AWG or smaller conductors. Terminals for more than one conductor and terminals used to connect aluminum shall be so identified."