As I flew in from UC and landed in Hammerfall, I immediately died. Nobody was nearby and I wondered what had killed me. I looked at my combat log to see that I was killed by a lvl 60.
However, he wasn’t in sight. I then realized that there was a mage camping right outside of the walls that were able to hug the walls and cast spells inside Hammerfall without aggroing the guards. They eventually got a group of 4 and camped the Wind Rider and killed anyone who land immediately.
This isn’t a bug, some private servers added additional LOS to objects but in vanilla/classic there was far less objects with LOS applied.
I suppose it’s possible that some areas/objects do not have the exact same LOS properties as they did in vanilla but it’s hard to say at this point. With that said it was not uncommon for ranged to hide behind objects such as trees while trying to snipe enemies.
Generally speaking in my experience, wood walls or walls comprised of wood stakes are not LOS objects.
The criteria for what is and what isn’t LOS isn’t very clear.