Opening the door seems to have something to do with clearing the fault.
It will probably never happen again, but if it does, try: turn off; open door, close door, see if problem cleared.
If that doesn't do it, I suppose you could try getting out, locking and unlocking the door, get back in.
2013 FFE Returned after 3 years with 52,000 miles and battery down to 15.2 kWh
2014 Volt returned with 43,000 miles
2014 Volt 26,000 miles
1967 Corvette 427
1962 Corvette 327
Awaiting a Bolt