I had the same problem recently, thankfully it was an irrelavent lvl 33 slaughter quest that I forgot to share with my lvl 38 boxes. But its defeinalty one of those "Oh god, did I really screw up and not get the quest all around?" moments inch: I didn't bother going and redoing it again, just moved on and hoped no one would ever know. Oops, guess admitting it kinda fubar'd that.