Aye, the effect can also be described as "rubber banding" to the target.
I've seen MovementProvider.StopMovement() fail on many occasions, and that caused this problem in the past. WingIt will continually retry stopping when this happens, as a large number of abilities cannot be used when in motion. But, if StopMovement() continues to fail, there is nothing to be done other than to update the direction to move (e.g., the "about face" to the target that you observe)--until the StopMovement() succeeds. Classes that can use Force Leap (and its not on cooldown) don't have this problem because it jumps directly to the target and stops implicitly.
All I can say is the root cause is probably some quirky interaction between Buddywing and SWtOR's Hero engine. Gosh knows, interacting with the Hero engine is simply a nightmare.
Check your logs for "GreyMagic" errors. If you've got any, you need to restart SWtOR, as Buddywing is not properly reading SWtOR memory.
cheers,
chinajade
Edit 1: On reflection, another cause of this problem in the past was the check for line-of-sight taking an excessively long time (hundreds of milliseconds) in some drops of SWtOR or Buddywing.