@tubetime I voted capacitor but in reality it is a parallel RC combination with 1 MĪ©

edit: Justify itā€¦ I'm not 100% shure but I think the reason was grounding the device's case this way enough against static electricity but not providing a real DC-path to prevent ground-loops (host grounds the shield directly, device never).

src: some friend at C3PB explained this as the ultimate solution to me