I have noticed a servo randomly move one or two degrees after it stops then it settles down and finally stops. I can hear it 'jiggling' or 'hunting' about a little then stops. Is this normal? Do I have a bad servo? It seems to do this worse at about 90 degrees. The sketch just positions the servo once. The servo is a HK-15138.
Check the links in my signature to ensure that you are powering the servo correctly.
Then if the movement is so small that you really have to look for it, its nothing to worry about, if its easily visible then come back once you have confirmed the power setup.