I have read the posts on fluttering mirror, mine does it too, only driver's side. No fix to this point. It is bad at highway speed.
Dealer supposedly replaced mirror once? kind of doubt they did... then mumbled about re-programming and a TSB. That is probably the re-cycling 3 times? fold them in and out 3 times? I always think it is just the mirror glass that flutters, never the whole housing...

What's the newest on this?

 

I don't know if it is the latest but flexing the metal tab that is supposed to rest against the inside of the mirror housing may help. If you flex it to make better contact with the inner wall it may stabilize the mirror face.

---Mirror face is mounted to ajustable inner controls. The tab goes fromthem tothe inner body of mirror housing. It allows the mirror face and controls to move but rests against the inner wall to stabilize the mirror.

 

???? that is way over my head... where is the tab? how do you get to it? and how do you bend it???