I am on a PvE server. Somehow I ended up PvP flagged and couldn't seem to turn it off. It stayed on when I got on a taxi. It didn't /pvp toggle off in five minutes. Having zero addons didn't have any effect. Right click on my character portrait showed it disabled. It would stop when I zoned into an instance, but sometimes it would manage to flip on inside and cause the old pvp disease. When zoning out of an instance I'd immediately be flagged PvP. It happened everywhere and anywhere.
This went on for almost a week.
I somehow figured it out by myself. It was thanks to this quest.