Originally Posted by
Confused Human
Yes, it does that. It's not lag, it's normal.
The tree issue you described is one of the most obvious examples, because you actually lose stuff from it. Same for flying mounts - once you reach a certain altitude, mobs and doodads outside your bubble disappear.
It's probably about bandwidth, the server only sends you the coordinates of objects inside your bubble, because it has no way of knowing if you have line of sight to them. If it did, it could phase things in or out more intelligently. Think z-buffer.