If you run across a 2020-2021 Toyota model with remote start and the customer concern is that the vehicle stays running after opening the front door (remote start), then you may want to replace the DCM.
2020 Highlanders may have an issue starting the vehicle after remote start.
The customer will remote start the car
The car will start
When the customer unlocks the car with the driver's oscillator, the vehicle will continue to run
When the customer tries to go out of park or start the car, the vehicle will turn off and will not run again for approx. 30min
I've had two of them so far, replacing the DCM resolved the issue. I posted the steps to register the DCM, and what the telematics data list should look like after registering. Hope this helps.