Guild Wars 2

This keeps happening to me while involved in underwater combat, I almost kill a mob and then they turn invincible, swim away and their health regenerates to full. Then they come back and attack fresh, often after I’m engaged in combat with a new mob. This has happened often enough now that it seems like a bug and not just a fluke.

This has been happening to me too; it’s quite frustrating as it usually happens just as their health is down to almost nothing. I just wanted to add in that occasionally I’ve had the same issue on land. I will attack an enemy and all of a sudden it will become invulnerable and will walk away and regenerate the lost health. I know it’s not an issue with me placing myself somewhere they can’t reach because it happens when I’m standing right next to them.

Seems to happen if you drift too far away from the mobs spawn/patrol points – they “give up” and run back.

It’s quite common and I actually think it’s a pathing issue. I’ve noticed it after getting the MOBs down part way through their health bar, however I have also noticed it on MOBs I am directly on top of or next to when combat is initiated. They start invincible. If you swim around them to a different location they will attack and die as normal. Since it seems they will behave properly from a different angle/direction, I will assume it is more a pathing issue than anything else.

Same happened to me, sometimes it’s my pet getting invulnerable when he attacks or me attacking in melee, happened on land, but more so in water.

I’ve had the same problem, and it’s been a persistent problem since game launch. Usually, I can fix it by swimming away from the mob. They will swim back to their start point and then start chasing me to reengage.

Incidentally, if I’m on my ranger, my pet can usually keep hitting the mob with no problem.

It happens to me too. But I don’t believe in being to far away from spawn point. The mob will usually move away only a very short distance. Then it rests for some seconds and after that it is attacking again.
As this happens with Bosses too, I am not fond of joining underwater boss events if there is NOT a big number of participants.