Automatic Transmission Gear Indicator problems of the 2018 GMC Acadia

2018 Acadia will display “shift to park” warning along with an audible warning when the vehicle is shut off. This happens even though the prndl display is in the “park” position each time. If I try to exit the vehicle, the audible warning continues (apparently indefinitely). This began at an odometer of about 59,200. Initially, the situation could be corrected by restarting the car and shifting in and out of park or depressing the shift knob several times. Within a couple of hundred miles, it became consistent and eventually could not be corrected as described above. Unfortunately, this is not covered under warranty. I began driving for a few months without the shift knob, simply depressing the plunger on the shift rod coming up from the transmission. Doing this, the warning rarely occurs and, if it does, it’s easily corrected with one or two presses of the plunger. Some modifications of the shift knob have allowed the knob to be used with results similar to driving without the knob. I hope there will be a software update (deployed over onstar) to use the prndl information and eliminate this failed system.