When I made a rogue, I noticed that hostile mobs of my own level didn't do what they did in retail vanilla when I moved into the far reach of their peripheral; stopping, looking at me, making an aggro noise, but not actually aggroing unless I continue to move into their view. I imagine anyone who's been perceptive while playing a stealth class in retail at any point in its life knows what I mean.
Am I lagging and being considered still moving in their view, so it foregoes the suspicion mechanic? Or is it simply not present? If so, is it a known bug?