Update: We believe the problem has been found, but the resolution is going to take a bit of work. The bug you are seeing crops up as a result of how the client and server are communicating when movement skills (any skill that forces you to move, or locks you in place) are used at the same time as the encounter scripts are forcing you to move.
Short term work around is to try not to use skills that lock you in place, or force you to move, when you are about to be teleported.
I wish I had a better answer, but we'll get it fixed asap.