Quiet does not seem to follow me like other buddies, is there a command to move her ?
I've also been having this issue - the trick is that you essentially have to redeploy her from the Buddy Support screen. This is found in the iDroid -> Missions -> Buddy Support.
When on the Support screen, you can select either of
Quiet (Scout) and
Quiet (Attack), which will relocate Quiet to a specific location, which you then select on the map.