I was looking at a battlereport I found pretty odd. The guy got medals for fast attack craft when there are no boats on that map, a rush medal when it was conquest, etc etc. How exactly does this happen? I have added the battlereport below for reference. 

http://battlelog.battlefield.com/bf4/battlereport/show/1/1087364293549332480/1004275145484/ 

It's a bug in the game's statics engine. The medals are assigned to the wrong game id, the round id, and are usually from a previous round. It has been around forever.