brake lights stuck on

My 2016 PIU, fresh from auction, has a brake light problem. They work just fine when the ignition is turned off or the key is in accessory mode. But when the key is in the run position they are stuck on. This includes all three brake lights in the back including the high mount. Here are things...

My brake lights (all 3) are sticking on, even after turning off the car. I've done lots of reading and there's some good points on older Explorers: Plastic stopper on the brake pedal is worn/gone, switch is corroded..., but this model has the electronically adjustable pedals, so they have a new...