The driver's side mirror on my Model 3 was replaced by a Tesla authorized repair center, after it was damaged when I was side-swiped by a pickup truck. Prior to repair, adjustments made to the mirror position held fine. Since the repair, the mirror gradually sags over about a 2 week period, ending up at the maximum downward adjustment. I can adjust it back to the proper position, but it again sags gradually; it's done this four times over the two month period since the repair. The repair center has not heard of this problem previously, and does not know what they can do to correct it. Any similar experiences or advice?