there is a bug in the new xp display I noticed - a bug in wow (maybe fixed since) but the display randomly shows ~3x more than it should (ie it shows 9x the base instead of 3x raf) - it seems related to how close/far other party members are (or maybe to chaining) but it's a display only (in the quest log) bug - if you check in the combat log the actual XP you get should be the correct one (usually lower than the one showed in quest log; but still 3x what you'd find mentioned in wowhead/thottbot for instance)

in other words; if you return that quest you'll probably get 7k xp on all characters and not 20k - and it should show something like "7k xp (4.6 k refer a friend bonus)"