Had driven from Northern CA to Southern CA, unpacked a student into a dorm room and then went shopping for housekeeping items & perishables. Store was less than 2 miles away.
Parked and shopped for maybe 80 minutes.
Got into the car in the store parking lot, turned the vehicle on and tried to toggle it into reverse and got no response. Turned off the vehicle. Thought something might have fallen into the switch and jammed it so tried cleaning around it.
Turned on the vehicle a couple times and switch was still not functioning normally.
Put the car into neutral to manually back it out of the space and drove to drop student and groceries off back at the dorm.
Parked and turned off vehicle.
Turned vehicle on again. System worked normally.
Turned off vehicle temporarily and turned it on again and got a transmission system error and rear navigation system error. Turned vehicle off and on a few times over the next 15 minutes. System worked normally again. Ran errand second day with no issue and later drove approximately 7 hours home. Have not had a recurrence of the problem but we’re now concerned about random transmisssion failure.
Googled it and found a few people with similar issue but no solution, technical bulletins, or or recalls.
Seems like maybe a software issue.
Any information or advice would be appreciated 
Also “Car Talk” used to be one of the highlights of my week, especially when on the road. I’ve learned so much from and always enjoyed everything from advice to puzzlers and stump the chumps. Glad the community is still here. Huge thanks to everyone!
You should still be in the warranty period so take to the dealer . Even if they don’t find a problem now at least it will be on record . It is also possible that they might even know what happened.
Thanks for the reply @VOLVO-V70.
It’s technically out of warranty (based on mileage) but I’ve read at least one post on a Pilot forum that there is an extended warranty (up to 80k) for transmission issues related to unpredictable acceleration and shifting delays, so I’m hoping maybe we’ll get lucky and this problem will be somehow related.
Since there are a few more posts out in the world about this as a problem specifically, I was hoping someone here might know about it and be able to provide enough info so I don’t get fleeced by the dealer service department.
Your powertrain is covered 5 yrs/60,000 miles, including the transmission:
“Transmission and Transaxle
Case and all internal parts, torque
converter, transfer case and all
internal parts, transmission/
powertrain control module, seals
and gaskets.”
Unfortunately, vehicle has 77k miles on it. 