Cayenne Adaptive Cruise Control (ACC)

[Jimease]

I have a 2019 Cayenne (base model). I had a trailer hitch installed by a Porsche approved collision repair shop as part of some rear bodywork repair. I tow a small Airstream Basecamp trailer, max weight of 3500 lbs. When towing, the Adaptive Cruise Control will stop working after about 50 miles. It will start working again at about the same distance after the trailer is disconnected. I've had it checked by a Porsche dealer after three of these incidents, but always after the ACC is working again. The dealer cannot find any problem, once they even suggested that it was caused by a dirty sensor in the grill that detects vehicles ahead. They clear what they call a passive fault in the computer and send me on my way.
It's been suggested that the ACC does not work if the vehicle is towing a trailer. If this is the case, I would think that the dealer would be aware of this. The ACC works perfectly if I'm not towing the trailer. I need the ACC to keep the speed down while towing. The Cayenne hardly notices the extra weight. It's hard to imagine why the ACC which is at the front of the car is affected by towing a trailer at the rear. I would expect the wiring for each to be completely separate.