I’m a new player so I’m not sure if this is intended to work this way or not, but it seemed like a bug to me. I was going through The Ruined Temple quest and got to the point where a bunch of enemies swarm you, and when you defeat them, it breaks the vines leading north so you can proceed.
The problem is, right at that point, before heading through where the vines had been, I decided to Town Portal. When I got back, the vines were back with no way to get rid of them. The enemies did not respawn so there was no way to kill them to trigger the destruction of the vines.
I ended up exiting the game and heading back out through the waypoint, and went through the whole zone again. When I got back to the same point the enemies there had come back, and I was able to get past the vines by killing them again.
All in all, not a huge deal, but it seems to me like once the vines go away they should stay gone.