Roadster charge port doors are not weatherproof, especially when they are open during charging.
Some customers may be charging outdoors, and if it rains or snows, this cavity behind the charge port door can fill up with water.
A closed charge port door does not provide a watertight seal, so pressure washing the Roadster, or car washes might be a secondary source of water ingress.
The problem is that the LED ring housing behind the body panel traps water, submerging the LED circuit board and input connector from the PEM.
The trapped water acts like an electrolyte during charging when the light ring is illuminated, and the 12 volts from the PEM begins an electroplating process, eating away etches on the PCB, or connector pins, including introducing corrosion and copper oxide.
Typical symptoms are a dim LED ring, one or some of the colors missing during charge, a dark ring during charge.
This LED ring is no longer in production, but is repairable.