I bugged this recently, but I want to say I have encountered this during Open Beta and may have during Closed. It was, and still is, a very small problem that does not happen much of the time.
Whenever I am in Ground Combat, mostly with NPCs but at times against players, my keys seem to switch actions. I will press "D" to go right and wind up going Left. Pressing "W" to go forwards makes me go backwards. This tends to most happen when I am crouched (pressing C) and am in a fire-fight. I sometimes stay in Crouch mode while moving (and keep firing) and this seems to happen most often while I am in that position. It also may have to do with the zoomed-in view Crouching gives you, but that is just a guess.
I don't think coming out of crouch solves this problem, but I am not sure. I know the problem goes away immediately after a fire-fight and sometimes during one (so...it MAY be coming out of Crouch solves it?)
It is a short-lived bug, but it has hampered me in some fire-fights.
When you have a target your movement is relative to that target. For instance, you have a target in front of you and all movement is as expected, if the target runs past you and gets behind you and you then press "forward" you will run towards the target, and in this example you will turn round and face him. and all movement becomed reversed.
The easiest way I have found to combat this is to hit the escape key and it drops the target. Failing that spin the camera around and movement will then return to normal.
I should point out that this is most noticable when you have "camera follow target" unticked in the camera options.
I think that is what you are referring to, i hope this helps.