Huh, interesting. I installed the outlet myself, to code, using the proper wiring. Voltage is usually around 230 but I did not specifically see what it was before the drop (or if it was at 30 amps from when I plugged it in). No warnings or messages given by the car.
I wonder if it could be caused by the compressor in a beer fridge on the same panel kicking on. I also have a Clipper Creek charger on the same panel (dedicated 40 amp breaker) for my i3 and have had both cars charging at the same time with no issues. Both are on a 100 amp sub panel with little else on the panel.
Seems random but at least this gives me a lead.