So, my wife pulls into the driveway in our 2015 Spark, puts the gear into Park, waits until the garage door opens (sometimes it's slow), then puts the the gear into Drive and the car goes... BACK, as in REVERSE! Needless to say, she did not expect it. I tell her to turn off the car and check it out myself: yep, you put the car into D or L, and it goes back. Being a contrarian, I put the car in Reverse... but it still goes back (not forward).
So, I disconnect the battery to flush whatever software code it keeps in battery-powered DRAM and to reboot it from some more permanent version of software. I reconnect the battery, restart the car, and now it is back to normal. So, my guess is some bit flipped in the memory. The car is still in warranty for another month, so I will take it for diagnostics. Anyone else experienced such weird behavior?