Needed: A Fix for the last Fix...
I would have to agree with OP, while it was an exploit in many ways to lure wurm outside of the circle, this solution ought to be more properly thought out. For a very short timer, it seems horribly unnecessary to make the wurm go invulnerable at all. Please change this.
As I said in the other thread discussing this topic:
I believe this is nothing more than an early “lets put something in quickly to prevent exploiting that doesn’t involve Shazbawt having to work 24/7”. A more permenant fix is most likely being worked on by the dev team.
I’m not saying that this is a “good” fix, it’s clearly broken in itself. But it means that people can’t cheat to earn the loot. That is the positive.
Personally, I think the best fix would be putting in a ledge just high enough to prevent the wurms from leaving the arena (won’t be pretty, but will work), or extend the area of the events significantly and allow the wurms to swim (underwater wurmbat!)