I've had that same thing happen a couple of times over the past month or so. When I crank it up I get a warning message about the power steering being unavailable, and the same thing about the trailer system. And, same as you, if I turn it off, let it sit, then back on it goes away (or, it has so far anyway). I took it to a couple of shops and no one seemed to be able to provide any insight. They suggested I take it to the dealer, but they're currently booked out like 2 months for appointments.
Just a frustrating issue because it happens so randomly, and without any real common thing to point to. I did recently get a new battery, but I had them check it and apparently the battery is giving a good reading. All of the connections seem to be tight as well.