I have had many, many situations where I'll hold X to disguise and my guy just spins around in circles trying to locate his target who is right below his feet. I even had one laggy match where I attempted a disguise while the player i was targeting respawned. I flew across the map, past the enemy camp's turrets to locate the player. It's wierd and sloppy.
It's probably too late to fix an issue like this with a patch too, which is the real bummer. It means Brink will ALWAYS have issues with this. For such a great game, that probably won't get a sequel, it's sad really.