Here is one Posting I bookmarked because it was the only one where the dealer could finally remedy it.I have a 2021 Yukon Dinali, and the driver side mirror fails to go back to its programmed position. It is intermittent, but when you turn the car off or when you’re close the car from the inside when parking, and then upon restarting the car the mirror goes all over the place and does not go back to its programmed spot. The dealer can’t seem to solve the problem. I think it’s a memory problem somewhere in the computer because but when this occurs I can always relocate the mirror with the internal switches and buttons and then save. Upon the next start it goes wherever it wants. I think this is a more general GMC computer programming problem
It seems they need to dig deeper and find an error code using the proper scanner and method.
Read below and perhaps . .. make a copy of it. . . . and show it to your dealer.
BTW . . this is ghe GMC Acadia forum, but the below may still help - - -
Ask the dealer to do a software update. I had struggled with this issue for over a year on my 2018 Acadia Denali. Took three trips to the Dealership. I've had the actuator replaced (a mechanical fix)...did not solve issue. I've replaced the battery in the fob...did not solve issue. I experienced every one of the issues noted by other posters above. And I heard all the same responses (i.e. cannot replicate). Felt like an idiot. But the issue was indeed real!
Finally, the foreman of the dealership got involved. After a series of tests, a code was returned of "unknown calibration" of the driver-specific memory settings. The software was then updated, which seems to have finally fixed it. In the end, modern cars are inescapably 'computers on wheels.' Hope this helps anyone else who may be encountering this issue.