If you've checked all the nuts and bolts on the mirror assembly and from the headlight fairing back and you still have trouble, try running a thin bead of black urethane of RTV silicon around the glass edge thous securing the glass to the metal/plastic surround. You may just have loose glass hopefully.
They do stick out a fair bit tho so it may be that there's too much wind resistance for the fairing to handle at higher speeds.
If it ok around town I wouldn't worry to much, that's about the only time you need them. Cruising at higher speeds you need to look where your going not where you've been