Thanks to player reports and feedback, we’ve identified a bug affecting how XP was calculated for parties of 6 or more players.
We are rolling out a hotfix right now, to all realms, that should correct this. Going forward, XP awarded should be significantly lower for parties of 6 or more players.
All the people? Game hasn’t even been out a week yet and relatively few people population-wide have used this exploit and there’s no real major case except SM (if not addressed it would surely grow to include more instances)