Mine was finally resolved after having the issues checked 6 times, battling it out with a SA and taking it up with the service manager.
It was finally replicable every time, mirrors would move when unlocking the car, and when they had moved, they wouldn't go back to stored memory positions. They replaced both motors and everything has been good now. It's been about a month and nothing has moved.
They told me "BMW Canada" doesn't have access to the service bulletins. I printed out the TSB text from this thread and wouldn't you know it, they followed it and it's fixed. I am out of factory warranty now but my extended covered the mirror so was all good.
2007 E90 328xi