Hi folks, So I opened the charge port door the other night, and this thing drops and rattles around the bottom of the portal. I didn't see where it came from. I had Henry's CAN JR in one hand, and opened the door with the other. The door opens really stiffly (takes two fingers under the opening and a strong tug to open it). It's black rubber, threaded on the inside. Bigger than a tire valve cap. Doesn't seem to go anywhere - in the charge portal, or on the CAN. Last place I had charged was at work, also using the CAN JR. Don't recall it being in there at that time. If someone said it landed there from outer space, I might believe them. It just appeared. Any clue where it goes?