2023Prime Plug-in charging malfunction warning

I had my 2023 Prime only a few days (certified used car, 2000 miles) when one morning, after a successful full charge, the Plug-in charging malfunction and check engine lights started flashing. The previous night I had tried to charge the car without realizing my outlet was off. I noticed the problem, unplugged the car on both ends, reset the outlet, plugged it all back in, and, as I said, successfully charged the car, then got the warning on starting the car the next morning. I took the car to the dealer, told the service guy, and he said the plug-in system was « blown » and I had caused it. He said the system needed to be replaced, it’ll take 3 weeks to get the parts. At first he told me to only drive in HV mode. I protested that 1. There is no way the car could be damaged by being plugged into an outlet with no current running through it and 2. if the system were « blown » I wouldn’t be able to charge the car fully and successfully. He suggested the problem was intermittent and told me to keep charging the car and driving it normally—after first telling me to only drive in HV mode! Meanwhile, he said he could not reset the codes until the car was « fixed », so I have the malfunction and check engine lights flashing at me still. I have no confidence in this place. I read here that a lot of people are getting this warning even though their cars are charging just fine, as mine continues to do. I am going to go in and talk to the service manager at the dealership.