Guild Wars 2

I’m having a hard time determining what makes a mob suddenly go Invulnerable. I have figured out the following circumstances cause Invulnerability reliably:

1. The mob can’t find a path to reach the player
2. The mob is running to the DE they’re intended to be in
3. The mob has been pulled too far from their spawn point
4. The mob is being sniped at from a different Z level

These are all understandable. 3 and 4 are a bit irritating sometimes but I can understand the mechanic. However, I have also had mobs go invulnerable on me in the middle of a fight, usually a long fight, with no apparent trigger. This is especially annoying since it will continue fighting and damaging me even though I can’t damage it (although sometimes I can kill it by inflicting conditions, which makes no sense). My wife has experienced this as well.

Does anyone know what exactly triggers this and how it can be avoided?

Biggest thing is z-level diffs. It’s anti exploitation measures to make sure mobs can hit you back, so you can’t kill mobs without risk. Sometimes it doesn’t take much to cause this to kick in.

In most cases when DEs with mobs involved end, the mobs are set to despawn, but they often run away for a while first so that they don’t just go poof, and those mobs aren’t really meant to be killed (although we do so often try!).

It especially happens underwater. Seems like it happens more the closer you are to the mob, so I wonder if it runs into a “divide by zero” type error where the AI can’t determine which direction you are from it.

It’s not hard to get it to happen, if you just run thru the mob repeatedly and jump n tumble a lot.

Best way to avoid it is to stand stationary in front of the mob. Not always a great idea.

What I hate is I’ll be standing on somewhere ~2 feet high and the mob can’t hit me. It’ll turn invulnerable and I’ll realize “oh he can’t hit me up here”. But even if I come down it takes a minute for him to become vulnerable again. I’ve inadvertently caused my Ascalon Catacombs (path 1) to fail a few times due to this.

Yeah, I have noticed it happens a lot underwater. I figured it was related to the z-level difference, which is obviously broken as underwater is a 3d playing field. I’ve /bug’d that one several times. I just wondered if there was some obvious trigger, like the length of the fight with a given target, that was causing it to happen in otherwise ordinary fights.

Dibrom.6408:

What I hate is I’ll be standing on somewhere ~2 feet high and the mob can’t hit me. It’ll turn invulnerable and I’ll realize “oh he can’t hit me up here”. But even if I come down it takes a minute for him to become vulnerable again. I’ve inadvertently caused my Ascalon Catacombs (path 1) to fail a few times due to this.

I’ve even had this happen to a ranged mob that was actually hitting me because I was standing on a spot it couldn’t path to. It seems like the game periodically runs a path-finding check on your targets, and if that check fails, makes them invulnerable regardless of their attack style.

I think it has a lot to do with Z level. It seems to happen a lot underwater when you’re right up close to a mob but above or below them. I’ve also had it happen with flying mobs. Also noticed it during theevents in Orr where the Risenattack the camps. When the waves of Risen start charging in they are often invulnerable for a time, en masse.

When it’s a spawn point leashing thing, and the mob runs back to its spawn/patrol point, I wish it would lose aggro also. But, nope, gets "home’ then races back to right where it was when it went invulnerable and commences to fight again. That one is all kinds of annoying.

I think you are basically right (although 1. and 4. are often the same thing) but sometimes the mob will agro someone else and while you have not met any of these conditions, the person who took agro might be on another level, etc.