Marauder stuck upon initiating combat

[Mopti]

Newb question. I've been playing a summoner and decided to try Marauder. Only with the Marauder, every time I initiate combat my character locks onto the target and I can't move until the mob is dead. Moving with the mouse doesn't work nor does movement with WASD. This movement problem does not happen with my Summoner. Thanks in advance.