The LS event Defeat the Mordrem champion in Iron Marches is an incredibly badly designed event. It is, quite seriously, MUCH easier to do solo than in a group. And it is a group event.
My experience with the mechanics of the boss are as such: After a long, obivous windup, the thrasher hits the ground and sends vines after things in the attack’s very large radius, much like Leeching Thrashers will. Unlike Leeching Thrashers, however, the vines cannot be avoided by moving, as the time between the vine appearing and it hitting you isn’t enough for you to move out of the way. They must be dodged or blocked.
The vine attack continues for a long time, OR until it is evaded. The problem is this: It will continue, against ALL affected targets, until ALL of them have in some way prevented it from hitting them. As such, the more people there are, the more likely there is someone who does not know how it works, which causes everyone else to continue getting hit. Worse still, it targets pets, and likely minions, illusions, spirit weapons, elementals, etc. that CANNOT DODGE, or in other words, Ranger CANNOT win against the boss due to its pet, unless maybe they intentionally get the pet killed?
The mechanic of the attack continuing until you avoid it is fine, but as it stands, where one person messing up breaks it for everyone, and pets mess it up regardless of what you do, it is broken.
Until it is changed, my advice: solo it, don’t play ranger (you lose automatically), and don’t play mesmer using any illusions at all (make sure to get rid of deceptive evasion too).
