There were multiple people from the guild Juizo Final on Darkhaven using an invulnerability exploit in WvW. It’s a spot near a supply camp they take zero damage, but are still able to damage opposing players.
The people exploiting were:
Rafael.2560
chapzin.4210
Dinamite.1084
Reasonplant.2195
Akunna.9254
Gera.5698
I have screenshots of them sitting in this spot.