Finally got my car back after 48 total days in a loaner car, 5 trips to the dealer and a whole lot of parts replaced. Cruise worked while on highway and hopefully it continues. It turns out there was a bad ground in a connector pin somewhere. Before finding that out they replaced the steering wheel cruise control switch, the brake switch, the engine ECM, and the complete engine wiring harness. He said they replaced most parts multiple times, put in 3 different ECM's and checked wiring etc repeatedly. They were in contact with Mazda and engineering and spent 45-50 man hours. Said engine wiring harness alone was oveer $3k. All this under warranty and no cost to me as car was only 4 months old when I dropped off with cruise control problem. After the five drop off's they finally just gave me loaner (2017 Camry) and said they would just keep until they fixed it. So they actually treated me well. I had nice car to drive but man what an ordeal for them. I sure hope it's fixed now. I imagine if it fails again they will either offer me buyback or I will pursue as it qualifies for lemon law at this point.