Mustang 2020 auto transmission fault

I have a 2020 mustang auto that had low gearbox
oil at service which was topped up. I was driving on
the freeway and it started slipping gears, lurching,
lost acceleration and it went into limp mode with
check engine light on.
The dealership acknowledge the computer showed
an error but they state they can’t replicate it..
I’m really concerned about driving it around and
getting stuck, causing an accident or worse..
any advice? It’s done 16,000 km and I have had it 8
months. Just serviced 4 days before the error..