I got my team to 40 so far and never saw that; and 1 or more member of my team is always 1 level behind or ahead [which bugs me, but that's a different topic] yet they still all get 3x xp in whichever order I return the quest; the only time it didn't happen for me was when I had hearted out to do repairs and turned in a cloth quest and then "opsa" because I had wasted the 3x because the peer toon wasn't around (so always remember to have everybody around when turning in) [well that and some green/grey quests where nobody got it]

I don't use a booster.